Ahh there is only no visible feedback. The extension is installed. But it doesn't work as of now. First nothing is stored with storage API so that my values are not saved. Additionally i fear that the bookmark API is not supported as of yet. But i will retry it later, when my extension at https://codeberg.org/Offerel/SyncMarks-Extension/ is fully supported.

Unfortunately this does not seem to work for me at least. Nautilus offers me to open it with "Web" and then Epiphany also opens. However, nothing else happens. Epiphany is version 45.1

Using gsettings list-keys org.gnome.Epiphany gives:

active-clear-data-items
ask-for-default
content-filters
default-search-engine
enable-caret-browsing
homepage-url
new-windows-in-tabs
restore-session-delaying-loads
restore-session-policy
search-engine-providers
search-engines
start-in-incognito-mode
use-google-search-suggestions
warn-on-close-unsubmitted-data

Shouldnt there be a enable-webextensions