1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2 3.. _fdl: 4 5****************************** 6GNU Free Documentation License 7****************************** 8 9 10.. _fdl-preamble: 11 120. PREAMBLE 13=========== 14 15The purpose of this License is to make a manual, textbook, or other 16written document "free" in the sense of freedom: to assure everyone the 17effective freedom to copy and redistribute it, with or without modifying 18it, either commercially or noncommercially. Secondarily, this License 19preserves for the author and publisher a way to get credit for their 20work, while not being considered responsible for modifications made by 21others. 22 23This License is a kind of "copyleft", which means that derivative works 24of the document must themselves be free in the same sense. It 25complements the GNU General Public License, which is a copyleft license 26designed for free software. 27 28We have designed this License in order to use it for manuals for free 29software, because free software needs free documentation: a free program 30should come with manuals providing the same freedoms that the software 31does. But this License is not limited to software manuals; it can be 32used for any textual work, regardless of subject matter or whether it is 33published as a printed book. We recommend this License principally for 34works whose purpose is instruction or reference. 35 36 37.. _fdl-section1: 38 391. APPLICABILITY AND DEFINITIONS 40================================ 41 42 43.. _fdl-document: 44 45This License applies to any manual or other work that contains a notice 46placed by the copyright holder saying it can be distributed under the 47terms of this License. The "Document", below, refers to any such manual 48or work. Any member of the public is a licensee, and is addressed as 49"you". 50 51 52.. _fdl-modified: 53 54A "Modified Version" of the Document means any work containing the 55Document or a portion of it, either copied verbatim, or with 56modifications and/or translated into another language. 57 58 59.. _fdl-secondary: 60 61A "Secondary Section" is a named appendix or a front-matter section of 62the :ref:`Document <fdl-document>` that deals exclusively with the 63relationship of the publishers or authors of the Document to the 64Document's overall subject (or to related matters) and contains nothing 65that could fall directly within that overall subject. (For example, if 66the Document is in part a textbook of mathematics, a Secondary Section 67may not explain any mathematics.) The relationship could be a matter of 68historical connection with the subject or with related matters, or of 69legal, commercial, philosophical, ethical or political position 70regarding them. 71 72 73.. _fdl-invariant: 74 75The "Invariant Sections" are certain 76:ref:`Secondary Sections <fdl-secondary>` whose titles are designated, 77as being those of Invariant Sections, in the notice that says that the 78:ref:`Document <fdl-document>` is released under this License. 79 80 81.. _fdl-cover-texts: 82 83The "Cover Texts" are certain short passages of text that are listed, as 84Front-Cover Texts or Back-Cover Texts, in the notice that says that the 85:ref:`Document <fdl-document>` is released under this License. 86 87 88.. _fdl-transparent: 89 90A "Transparent" copy of the :ref:`Document <fdl-document>` means a 91machine-readable copy, represented in a format whose specification is 92available to the general public, whose contents can be viewed and edited 93directly and straightforwardly with generic text editors or (for images 94composed of pixels) generic paint programs or (for drawings) some widely 95available drawing editor, and that is suitable for input to text 96formatters or for automatic translation to a variety of formats suitable 97for input to text formatters. A copy made in an otherwise Transparent 98file format whose markup has been designed to thwart or discourage 99subsequent modification by readers is not Transparent. A copy that is 100not "Transparent" is called "Opaque". 101 102Examples of suitable formats for Transparent copies include plain ASCII 103without markup, Texinfo input format, LaTeX input format, SGML or XML 104using a publicly available DTD, and standard-conforming simple HTML 105designed for human modification. Opaque formats include PostScript, PDF, 106proprietary formats that can be read and edited only by proprietary word 107processors, SGML or XML for which the DTD and/or processing tools are 108not generally available, and the machine-generated HTML produced by some 109word processors for output purposes only. 110 111 112.. _fdl-title-page: 113 114The "Title Page" means, for a printed book, the title page itself, plus 115such following pages as are needed to hold, legibly, the material this 116License requires to appear in the title page. For works in formats which 117do not have any title page as such, "Title Page" means the text near the 118most prominent appearance of the work's title, preceding the beginning 119of the body of the text. 120 121 122.. _fdl-section2: 123 1242. VERBATIM COPYING 125=================== 126 127You may copy and distribute the :ref:`Document <fdl-document>` in any 128medium, either commercially or noncommercially, provided that this 129License, the copyright notices, and the license notice saying this 130License applies to the Document are reproduced in all copies, and that 131you add no other conditions whatsoever to those of this License. You may 132not use technical measures to obstruct or control the reading or further 133copying of the copies you make or distribute. However, you may accept 134compensation in exchange for copies. If you distribute a large enough 135number of copies you must also follow the conditions in 136:ref:`section 3 <fdl-section3>`. 137 138You may also lend copies, under the same conditions stated above, and 139you may publicly display copies. 140 141 142.. _fdl-section3: 143 1443. COPYING IN QUANTITY 145====================== 146 147If you publish printed copies of the :ref:`Document <fdl-document>` 148numbering more than 100, and the Document's license notice requires 149:ref:`Cover Texts <fdl-cover-texts>`, you must enclose the copies in 150covers that carry, clearly and legibly, all these Cover Texts: 151Front-Cover Texts on the front cover, and Back-Cover Texts on the back 152cover. Both covers must also clearly and legibly identify you as the 153publisher of these copies. The front cover must present the full title 154with all words of the title equally prominent and visible. You may add 155other material on the covers in addition. Copying with changes limited 156to the covers, as long as they preserve the title of the 157:ref:`Document <fdl-document>` and satisfy these conditions, can be 158treated as verbatim copying in other respects. 159 160If the required texts for either cover are too voluminous to fit 161legibly, you should put the first ones listed (as many as fit 162reasonably) on the actual cover, and continue the rest onto adjacent 163pages. 164 165If you publish or distribute :ref:`Opaque <fdl-transparent>` copies of 166the :ref:`Document <fdl-document>` numbering more than 100, you must 167either include a machine-readable :ref:`Transparent <fdl-transparent>` 168copy along with each Opaque copy, or state in or with each Opaque copy a 169publicly-accessible computer-network location containing a complete 170Transparent copy of the Document, free of added material, which the 171general network-using public has access to download anonymously at no 172charge using public-standard network protocols. If you use the latter 173option, you must take reasonably prudent steps, when you begin 174distribution of Opaque copies in quantity, to ensure that this 175Transparent copy will remain thus accessible at the stated location 176until at least one year after the last time you distribute an Opaque 177copy (directly or through your agents or retailers) of that edition to 178the public. 179 180It is requested, but not required, that you contact the authors of the 181:ref:`Document <fdl-document>` well before redistributing any large 182number of copies, to give them a chance to provide you with an updated 183version of the Document. 184 185 186.. _fdl-section4: 187 1884. MODIFICATIONS 189================ 190 191You may copy and distribute a :ref:`Modified Version <fdl-modified>` 192of the :ref:`Document <fdl-document>` under the conditions of sections 193:ref:`2 <fdl-section2>` and :ref:`3 <fdl-section3>` above, provided 194that you release the Modified Version under precisely this License, with 195the Modified Version filling the role of the Document, thus licensing 196distribution and modification of the Modified Version to whoever 197possesses a copy of it. In addition, you must do these things in the 198Modified Version: 199 200- **A.** 201 Use in the :ref:`Title Page <fdl-title-page>` (and on the covers, 202 if any) a title distinct from that of the 203 :ref:`Document <fdl-document>`, and from those of previous versions 204 (which should, if there were any, be listed in the History section of 205 the Document). You may use the same title as a previous version if 206 the original publisher of that version gives permission. 207 208- **B.** 209 List on the :ref:`Title Page <fdl-title-page>`, as authors, one or 210 more persons or entities responsible for authorship of the 211 modifications in the :ref:`Modified Version <fdl-modified>`, 212 together with at least five of the principal authors of the 213 :ref:`Document <fdl-document>` (all of its principal authors, if it 214 has less than five). 215 216- **C.** 217 State on the :ref:`Title Page <fdl-title-page>` the name of the 218 publisher of the :ref:`Modified Version <fdl-modified>`, as the 219 publisher. 220 221- **D.** 222 Preserve all the copyright notices of the 223 :ref:`Document <fdl-document>`. 224 225- **E.** 226 Add an appropriate copyright notice for your modifications adjacent 227 to the other copyright notices. 228 229- **F.** 230 Include, immediately after the copyright notices, a license notice 231 giving the public permission to use the 232 :ref:`Modified Version <fdl-modified>` under the terms of this 233 License, in the form shown in the Addendum below. 234 235- **G.** 236 Preserve in that license notice the full lists of 237 :ref:`Invariant Sections <fdl-invariant>` and required 238 :ref:`Cover Texts <fdl-cover-texts>` given in the 239 :ref:`Document's <fdl-document>` license notice. 240 241- **H.** 242 Include an unaltered copy of this License. 243 244- **I.** 245 Preserve the section entitled "History", and its title, and add to it 246 an item stating at least the title, year, new authors, and publisher 247 of the :ref:`Modified Version <fdl-modified>` as given on the 248 :ref:`Title Page <fdl-title-page>`. If there is no section entitled 249 "History" in the :ref:`Document <fdl-document>`, create one stating 250 the title, year, authors, and publisher of the Document as given on 251 its Title Page, then add an item describing the Modified Version as 252 stated in the previous sentence. 253 254- **J.** 255 Preserve the network location, if any, given in the 256 :ref:`Document <fdl-document>` for public access to a 257 :ref:`Transparent <fdl-transparent>` copy of the Document, and 258 likewise the network locations given in the Document for previous 259 versions it was based on. These may be placed in the "History" 260 section. You may omit a network location for a work that was 261 published at least four years before the Document itself, or if the 262 original publisher of the version it refers to gives permission. 263 264- **K.** 265 In any section entitled "Acknowledgements" or "Dedications", preserve 266 the section's title, and preserve in the section all the substance 267 and tone of each of the contributor acknowledgements and/or 268 dedications given therein. 269 270- **L.** 271 Preserve all the :ref:`Invariant Sections <fdl-invariant>` of the 272 :ref:`Document <fdl-document>`, unaltered in their text and in 273 their titles. Section numbers or the equivalent are not considered 274 part of the section titles. 275 276- **M.** 277 Delete any section entitled "Endorsements". Such a section may not be 278 included in the :ref:`Modified Version <fdl-modified>`. 279 280- **N.** 281 Do not retitle any existing section as "Endorsements" or to conflict 282 in title with any :ref:`Invariant Section <fdl-invariant>`. 283 284If the :ref:`Modified Version <fdl-modified>` includes new 285front-matter sections or appendices that qualify as 286:ref:`Secondary Sections <fdl-secondary>` and contain no material 287copied from the Document, you may at your option designate some or all 288of these sections as invariant. To do this, add their titles to the list 289of :ref:`Invariant Sections <fdl-invariant>` in the Modified Version's 290license notice. These titles must be distinct from any other section 291titles. 292 293You may add a section entitled "Endorsements", provided it contains 294nothing but endorsements of your 295:ref:`Modified Version <fdl-modified>` by various parties--for 296example, statements of peer review or that the text has been approved by 297an organization as the authoritative definition of a standard. 298 299You may add a passage of up to five words as a 300:ref:`Front-Cover Text <fdl-cover-texts>`, and a passage of up to 25 301words as a :ref:`Back-Cover Text <fdl-cover-texts>`, to the end of the 302list of :ref:`Cover Texts <fdl-cover-texts>` in the 303:ref:`Modified Version <fdl-modified>`. Only one passage of 304Front-Cover Text and one of Back-Cover Text may be added by (or through 305arrangements made by) any one entity. If the 306:ref:`Document <fdl-document>` already includes a cover text for the 307same cover, previously added by you or by arrangement made by the same 308entity you are acting on behalf of, you may not add another; but you may 309replace the old one, on explicit permission from the previous publisher 310that added the old one. 311 312The author(s) and publisher(s) of the :ref:`Document <fdl-document>` 313do not by this License give permission to use their names for publicity 314for or to assert or imply endorsement of any 315:ref:`Modified Version <fdl-modified>`. 316 317 318.. _fdl-section5: 319 3205. COMBINING DOCUMENTS 321====================== 322 323You may combine the :ref:`Document <fdl-document>` with other 324documents released under this License, under the terms defined in 325:ref:`section 4 <fdl-section4>` above for modified versions, provided 326that you include in the combination all of the 327:ref:`Invariant Sections <fdl-invariant>` of all of the original 328documents, unmodified, and list them all as Invariant Sections of your 329combined work in its license notice. 330 331The combined work need only contain one copy of this License, and 332multiple identical :ref:`Invariant Sections <fdl-invariant>` may be 333replaced with a single copy. If there are multiple Invariant Sections 334with the same name but different contents, make the title of each such 335section unique by adding at the end of it, in parentheses, the name of 336the original author or publisher of that section if known, or else a 337unique number. Make the same adjustment to the section titles in the 338list of Invariant Sections in the license notice of the combined work. 339 340In the combination, you must combine any sections entitled "History" in 341the various original documents, forming one section entitled "History"; 342likewise combine any sections entitled "Acknowledgements", and any 343sections entitled "Dedications". You must delete all sections entitled 344"Endorsements." 345 346 347.. _fdl-section6: 348 3496. COLLECTIONS OF DOCUMENTS 350=========================== 351 352You may make a collection consisting of the 353:ref:`Document <fdl-document>` and other documents released under this 354License, and replace the individual copies of this License in the 355various documents with a single copy that is included in the collection, 356provided that you follow the rules of this License for verbatim copying 357of each of the documents in all other respects. 358 359You may extract a single document from such a collection, and distribute 360it individually under this License, provided you insert a copy of this 361License into the extracted document, and follow this License in all 362other respects regarding verbatim copying of that document. 363 364 365.. _fdl-section7: 366 3677. AGGREGATION WITH INDEPENDENT WORKS 368===================================== 369 370A compilation of the :ref:`Document <fdl-document>` or its derivatives 371with other separate and independent documents or works, in or on a 372volume of a storage or distribution medium, does not as a whole count as 373a :ref:`Modified Version <fdl-modified>` of the Document, provided no 374compilation copyright is claimed for the compilation. Such a compilation 375is called an "aggregate", and this License does not apply to the other 376self-contained works thus compiled with the Document , on account of 377their being thus compiled, if they are not themselves derivative works 378of the Document. If the :ref:`Cover Text <fdl-cover-texts>` 379requirement of :ref:`section 3 <fdl-section3>` is applicable to these 380copies of the Document, then if the Document is less than one quarter of 381the entire aggregate, the Document's Cover Texts may be placed on covers 382that surround only the Document within the aggregate. Otherwise they 383must appear on covers around the whole aggregate. 384 385 386.. _fdl-section8: 387 3888. TRANSLATION 389============== 390 391Translation is considered a kind of modification, so you may distribute 392translations of the :ref:`Document <fdl-document>` under the terms of 393:ref:`section 4 <fdl-section4>`. Replacing 394:ref:`Invariant Sections <fdl-invariant>` with translations requires 395special permission from their copyright holders, but you may include 396translations of some or all Invariant Sections in addition to the 397original versions of these Invariant Sections. You may include a 398translation of this License provided that you also include the original 399English version of this License. In case of a disagreement between the 400translation and the original English version of this License, the 401original English version will prevail. 402 403 404.. _fdl-section9: 405 4069. TERMINATION 407============== 408 409You may not copy, modify, sublicense, or distribute the 410:ref:`Document <fdl-document>` except as expressly provided for under 411this License. Any other attempt to copy, modify, sublicense or 412distribute the Document is void, and will automatically terminate your 413rights under this License. However, parties who have received copies, or 414rights, from you under this License will not have their licenses 415terminated so long as such parties remain in full compliance. 416 417 418.. _fdl-section10: 419 42010. FUTURE REVISIONS OF THIS LICENSE 421==================================== 422 423The `Free Software Foundation <http://www.gnu.org/fsf/fsf.html>`__ 424may publish new, revised versions of the GNU Free Documentation License 425from time to time. Such new versions will be similar in spirit to the 426present version, but may differ in detail to address new problems or 427concerns. See 428`http://www.gnu.org/copyleft/ <http://www.gnu.org/copyleft>`__. 429 430Each version of the License is given a distinguishing version number. If 431the :ref:`Document <fdl-document>` specifies that a particular 432numbered version of this License "or any later version" applies to it, 433you have the option of following the terms and conditions either of that 434specified version or of any later version that has been published (not 435as a draft) by the Free Software Foundation. If the Document does not 436specify a version number of this License, you may choose any version 437ever published (not as a draft) by the Free Software Foundation. 438 439 440.. _fdl-using: 441 442Addendum 443======== 444 445To use this License in a document you have written, include a copy of 446the License in the document and put the following copyright and license 447notices just after the title page: 448 449 Copyright �� YEAR YOUR NAME. 450 451 Permission is granted to copy, distribute and/or modify this 452 document under the terms of the GNU Free Documentation License, 453 Version 1.1 or any later version published by the Free Software 454 Foundation; with the :ref:`Invariant Sections <fdl-invariant>` 455 being LIST THEIR TITLES, with the 456 :ref:`Front-Cover Texts <fdl-cover-texts>` being LIST, and with 457 the :ref:`Back-Cover Texts <fdl-cover-texts>` being LIST. A copy 458 of the license is included in the section entitled "GNU Free 459 Documentation License". 460 461If you have no :ref:`Invariant Sections <fdl-invariant>`, write "with 462no Invariant Sections" instead of saying which ones are invariant. If 463you have no :ref:`Front-Cover Texts <fdl-cover-texts>`, write "no 464Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise 465for :ref:`Back-Cover Texts <fdl-cover-texts>`. 466 467If your document contains nontrivial examples of program code, we 468recommend releasing these examples in parallel under your choice of free 469software license, such as the 470`GNU General Public License <http://www.gnu.org/copyleft/gpl.html>`__, 471to permit their use in free software. 472