Improve TiddlyWiki licensing implementation

[Jermolene]

There are several aspects of TiddlyWiki which need to carry licensing information:

• The TiddlyWiki core code
• The content within a TiddlyWiki instance
• Plugins designed for TiddlyWiki, and
  ** Third-party libraries incorporated into those plugins

The present situation is that the core plugin carries a license in $:/core/copyright.txt which is automatically inserted into generated HTML files. Core plugins include the license files for the third party libraries that they include, but these licenses are not retained as shadow tiddlers within the plugins. There is no explicit support for marking the license of the content of a TiddlyWiki.

Some of the problems with the current situation were explored in this thread. A key issue is that looking at the source code of a TiddlyWiki HTML file prominently displays the core BSD license, giving the impression that it applies to the entire content of the file.

It is proposed to:

• Adopt a convention for all plugins to include zero or more copyright/license tiddlers with the tag $:/tags/License. By convention the main license for a plugin would be called <plugin-title>/license or <plugin-title>/copyright.txt
• Each license tiddler should have the text of the license agreement and a license-type field giving the short name of the license (need to research the best unique license identifiers to use)
• Adopt a convention that the content of a TiddlyWiki is covered by a $:/tags/License tiddler called $:/ContentLicense. Provide a user interface for selecting a license in the control panel
• Present a unified view of all license tiddlers into the control panel
• Bake the text of all the license tiddlers into generated HTML files. Put the non-shadow licenses first, then the core license, then any other shadow licenses

[sukima]

That all sounds good!

[pmario]

@Jermolene ... I think you did implement this. right?

[Jermolene]

Hi @pmario no, this still isn't done, and I think it would be desirable as our acknowledgements are important and yet scattered and inaccessible at the moment.

[ghost]

What can be done with the current codebase to make it easier to transition the current plugins to use this new license scheme?

[Jermolene]

Hi @Zacts I think it's just a matter of locating all the third party libraries used in the TW5 repo, and then performing the steps outlined in the OP.

[fkohrt]

I really like the ideas proposed here!

need to research the best unique license identifiers to use

@Jermolene This already exists: SPDX License List. Also relevant: REUSE Specification