When releasing this to AMO, make sure that the extension ID is the same as as the old extesion

[ExE-Boss]

Private_Tab_WE/manifest.json

Line 10 in 68dce4d

"id": "privateTabWE@infocatcher"

This should instead be privateTab@infocatcher as per MDN documentation (step 4).

This way, everyone who used the legacy extension will get updated to the WebExtension.

[Infocatcher]

Yes, but currently WE version isn't functional due to API limitations, so I prefer to have both installed (it's still possible to apply some hacks to use legacy extensions).
And later I'll change ID like here: Infocatcher/Right_Links_WE@25b2c39