Mosaic upgrade to Plone 6 mini sprint

A popular add'on for Plone 5.X which is not in core is, a composited page builder. To bring Mosaic to Plone 6 'classic ui', a mini sprint will be held this friday.

Updating to Plone 6 depends heavily on the almost finished grand effort to upgrade Plone 6's default theme support to Bootstrap 5, remove require.js and rebuild the javascript (Mockup) patterns to support ESM .

The sprint will be coordinated using our Discord server, please check the #classic-ui channel or use this access link to the channel to connect.