To get old tab bars on Safari for macOS 12, create
/Library/Preferences/FeatureFlags/Domain/Safari.plist
copy the above into it, and reboot.
The feature is controlled by
+[FeatureAvailability isUnifiedBarEnabled]
which calls os_feature_enabled
, which searches in /System/Library/FeatureFlags/Domain/Safari.plist
and /Library/Preferences/FeatureFlags/Domain/Safari.plist
.
I copied the System file, removed the other flags, and changed UnifiedBar to false.
Any disassembler will do the job.
It's quite easy to write a patch, but it will require to re-sign all "Safari Tech Preview" frameworks and binaries. For an app that is updated every 2 weeks and for which a new patch will be required each time, I'm not sure this is worth it.
Especially as Apple is free to completely remove this escape hatch at any time.