Go through the following pointers and break down into tasks the steps needed to implement the primary sources tool as a MediaWiki extension.

• https://www.mediawiki.org/wiki/Manual:Extensions
• https://www.mediawiki.org/wiki/Manual:Developing_extensions
• https://www.mediawiki.org/wiki/Manual:Hooks
• https://www.mediawiki.org/wiki/Category:User_interface_extensions

HTML templates that actually are in use on Wikidata:
https://github.com/wikimedia/mediawiki-extensions-Wikibase/blob/master/view/resources/templates.php
We could add our php files in Wikibase repo and use templates.php for compare the names of the HTML classes.

Wikibase is formed by componets (link). We can move "primary sources tool" to Wikibase as a community tool.

In T166496#3298609, @Afnecors wrote:

HTML templates that actually are in use on Wikidata:
https://github.com/wikimedia/mediawiki-extensions-Wikibase/blob/master/view/resources/templates.php
We could add our php files in Wikibase repo and use templates.php for compare the names of the HTML classes.

This seems more related to T166513: linked for reference.

In T166496#3300505, @Afnecors wrote:

Wikibase is formed by componets (link). We can move "primary sources tool" to Wikibase as a community tool.

same comment above applies: T166513

Thanks to the documentation and the investigation of existing extensions we identified a few core files we'll need to produce to obtain a working extension:

• extension body file to store the execution code
• hooks.php file to define the callback functions called by the hooks
• message and message documentation files to add support for localisation
• modules files to include the JS and the CSS with the ResourceLoader
• API file to extend the basic API functions
• extension.json file for extension registration