While updating a theme to Plone6, I noticed that a piece of js that performs cosmetic fixes stopped working. This is because it was looking for PORTAL_URL in the DOM of the page, and this is now gone in Plone6... Lucklily, the value is still available, but now as base_url
I got curious and started searching as to what caused this change and why, but can"t seem to find anything more recent than the removal of plone_javascript_variables in 2015 and some GitHub chatter from 2017.