Add all localised URLs of each path as locations and add every localised URL of each location as alternate to each location... :P

Remove options variable (containing language objects etc) from array passed to sitemap generator to save resources

Clean up a few classes, prevent simple_sitemap service from loading xml sitemap chunks from DB on every initialization

Fix regression introduced in 8.x-2.4 which prevents from excluding content which has been included once.

Issue #2684771 by Sam152: Update LinkGeneratorInterface to enforce what link generators need to provide

Fixing wrong language codes in custom url generation, fixing wrong date format in sitemap, improving duplicate prevention and annotating some code.

Further plugins, improving the handling of custom paths, adding some more error handling, various fixes.

Plugins can now add link options (url parameters and anchors). Sitemap now accepts url parameters and anchors.