Document css_styled_content rendering changes in compat_version
We have an array in css_styled_content in ext_localconf.php (compat_version) which is used by the Upgrade Wizard to inform the user of what has changed in the FE-rendering if he "upgrades" his compat version to the latest version (which is recommended).
The rule in the Core has been to add an entry for every change that was made to the rendering in css_styled_content. This hasn't been done since 4.5 as it seems, which then results in the upgrader not getting any info at all at this point of the wizard what has been changed.
In the sense of Smooth migration we should at least document the major changes since 4.5 to the 6.2 version. I would propose not to backport these back to 4.6 .. 6.1 as it is not worth it. And we don't need to document every individual step but instead could summarize the major changes that happened between the versions instead.