In version 3.0, where token where used, the extension icon switched from grey to orange when the website was compatible with (legacy) Privacy Pass protocol.
A similar pattern could be used for the extension when it's actively responding to a PrivateToken challenge.
This would help user get insight at whether the extension is helpful to them, as has been reported in privacypass/challenge-bypass-extension#407.
In version 3.0, where token where used, the extension icon switched from grey to orange when the website was compatible with (legacy) Privacy Pass protocol.
A similar pattern could be used for the extension when it's actively responding to a PrivateToken challenge.
This would help user get insight at whether the extension is helpful to them, as has been reported in privacypass/challenge-bypass-extension#407.