There is no table of the actual status of extensions at https://extensions.libreoffice.org/ This table can have the first LO Version going and the last Version. With this table, the user can see the actual possible extensions without the obsolete. There is no automatic installation testing of the developers by new versions of LO. There is no automatic review of these installation problems to the extension developers. There is no information about obsolete extensions by better LO with inside features. Extensions are important for many users and often there are the idols of new features in LO. These processes and the website https://extensions.libreoffice.org/ should be improved. An automatic extension code tester with the actual LO-Extensions-API-commands is here an idea. An example of an interesting extension is https://extensions.libreoffice.org/en/extensions/show/digitizer-of-xy-chart compatible with LO 3.3, but the highest Version of compatibility is not specified. It is running also in LO 4 and 5. And in LO 6.4 and 7.0 with installation error.
chart digitizer is running from 3.3 to LO 6.2.8.2. With 6.3 a great change in LO makes many older extensions obsolete. Also, actual extensions are not in the catalog like Grammalecte for french users from Grammalecte.net.
Please report this in Redmine https://redmine.documentfoundation.org/projects/extensions/issues