Obtaining extension identifier from Microsoft Edge add-on Web Store:
Lets consider 'adblock' as the extension to be added to the extension repository:
- Go to Microsft add-on web store.
- Search for the extension using the search bar.
- From the URL address bar, select the extension identifier which is located after "/" as displayed in the image below.
- Copy the identifier and paste it in the Extension Identifier field present in the Extension Repository.