How do I do the same when using GeckoView?
Additional System Details
- User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36
This is an end user support forum. Geckoview questions should be asked at the options provided at https://wiki.mozilla.org/Mobile/GeckoView#Getting_Help
https://mozilla.github.io/geckoview/consumer/docs/web-extensions may be of some help.