For anyone looking for the source code for the GSNv1 Relayer:
The instructions for running a relayer are here: https://gist.github.com/spalladino/f516b46bdefb5e025c5d28daf7ad1491
There’s also a dockerized version here JUDOKICK/matic-gsn-relayer-creol
The repository for the relayer is: opengsn/gsn_v1
Please note, there is a patch pending: opengsn/gsn_v1#6
You can get a pre-built version with that fix here: https://github.com/OpenZeppelin/gsn-relayer/releases/tag/v0.4.6
If you have any issues, you can ask on the OpenGSN Telegram: https://t.me/joinchat/F_BETUjG0Crb2s6mFx1LWA