activating cep development mode
Debugging Unsigned Extensions
If you are in the midst of development and are not using HTML Extension Builder for debug workflows and want to bypass the need to sign your extensions, you can bypass the check for extension signatures by editing the CSXS preference properties file, located at:
Win: regedit > HKEY_CURRENT_USER/Software/Adobe/CSXS.8, then add a new entry PlayerDebugMode of type "string" with the value of "1".
Mac: In the terminal, type: defaults write com.adobe.CSXS.8 PlayerDebugMode 1 (The plist is also located at /Users/<username>/Library/Preferences/com.adobe.CSXS.8.plist)
These entries will enable debug extensions to be displayed in the host applications. Please note that, CSXS.8 is given with the assumption that, you are developing the extension for CEP 8. If you are developing extension for previous version of CEP, replace 8 with corresponding version number.
Special notes for Mac 10.9 and higher
Staring with Mac 10.9, Apple introduced a caching mechanism for plist files. Your modifications to plist files does not take effect until the cache gets updated (on a periodic basis, you cannot know exactly when the update will happen). To make sure your modifications take effect, there are two methods.
Kill cfprefsd process. It will restart automatically. Then the update takes effect.
Restart your Mac, or log out the current user and re-log in.
Please note that running CEP extensions in Photoshop 2022 with UXP developer
mode activated will cause a "not properly signed" error. Try using older
Photoshops to debug ro develop CEP extensions.