Does 3.7 alter the sclang_conf.yaml file to add Extensions ? I don't think so.
AFAIK Extensions is no longer automatically added to the compile path.
This is all that is included automatically:
SCClassLibrary ❯ ls
Common
DefaultLibrary
JITLib
Platform
SCDoc
backwards_compatibility
deprecated
scide_scqt
So there is no conflict.
The 3.7 quarks system could check, on any install/update operation, for the
existence of Extensions/quarks and at least warn the user of a possible
conflict.