[emi2k01]

Search is disabled for forked repositories in github. It's better to create a new repo and push the code if you want a fork.

Search in original repo works: https://github.com/mozilla/send/search?l=javascript

[circularfoyers]

The other option too would be just to clone the repo locally and use grep, find, etc. That seems the simpler option if you just want to perform a search.

[bakje]

Or open the repo in github1s so you don't have to clone anything: https://github1s.com/timvisee/send/

For more info see: https://github.com/conwnet/github1s