Does the bootloader need to be unlocked to install the F-Droid Privileged Extension OTA .zip?

The question is basically in the title: Does the bootloader need to be unlocked (fastboot flashing unlock/fastboot oem unlock) to install the F-Droid Privileged Extension OTA .zip? I wouldn’t have thought so, but I found this bug report today, which includes the following steps:

  1. Booted phone, installed all updates, and rebooted (also disabled Play Protect harmful app detection)
  2. Enabled developer options and OEM unlocking
  3. Powered off phone and booted to fastboot
  4. Unlocked bootloader (fastboot flashing unlock), then booted
  5. Copied FDroid.apk to phone and installed from Files
  6. Opened F-droid and enabled Expert mode; privileged extension option no present
  7. Powered off phone and booted to fastboot
  8. Booted to TWRP (fastboot boot /tmp/twrp/twrp-3.3.1-1-sargo.img)
  9. Pushed org.fdroid.fdroid.privileged.ota_2090.zip (using adb push) to device
  10. Installed org.fdroid.fdroid.privileged.ota_2090.zip using TWRP Install feature (no errors reported)
  11. Wiped Dalvik
  12. Used adb shell to confirm presence of (/system/system seems to be where the system partition is mounted in TWRP):
    • /system/system/app/F-Droid/F-Droid.apk
    • /system/system/priv-app/F-DroidPrivilegedExtension/F-DroidPrivilegedExtension.apk
    • /system/system/etc/permissions/permissions_org.fdroid.fdroid.privileged.xml
  13. Rebooted

In particular, I don’t understand the purpose of “2. Enabled developer options and OEM unlocking, 3. Powered off phone and booted to fastboot, 4. Unlocked bootloader (fastboot flashing unlock), then booted”.

Well yes…you can’t install it in /system/ otherwise.

Ah, OK, I was assuming that “locked bootloader” was only referring to, well, the bootloader itself being locked, not additional parts like /system/. Thanks!

No it certainly does not. I never unlocked my bootloader.
I just have ROOT access and used System App Mover
https://f-droid.org/packages/de.j4velin.systemappmover/

Depends on device, eg. Not needed for Sony Z3
But most? Might need it…