The same issue as reported for UDM hooks and fixed via Bug #57630 also applies to UDM syntax extensions. The sandboxing import that is now used for UDM hooks may cause regressions for UDM syntax extensions in case authors didn't explicitly import dependencies but relied on implicit prior imports in the global namespace. We need to find a middle ground here or use some kind of UCS release to communicate the possible breaking change and give customers proper time for testing and possibly required adjustments.
MR: https://git.knut.univention.de/univention/dev/ucs/-/merge_requests/1573