This plugin mimics Emark plugin Extension for Chrome. The difference that this extension doesn't contain any external dependencies or requests, except the Roboto font loading. And it works on Firefox.
I asked the author of the original Embark about his port to Firefox in 2017, but it's still not a thing. So, I've decided to make my own. This plugin has a subset of options that I prefer to use, but all PRs are welcome.
I didn't publish it on Firefox Extensions, but you can submit it as self-distributed on Mozilla's Add-on Developer Hub. If you want to see it as a common extension, feel free to create an issue about it.
Photos of mountains are from Unsplash. Kudos to their authors.
yarn && yarn build
mogrify -geometry x1080 *.jpg