Hey Uday, let me explain more what's expected to be done in this report.
Firefox DevTools allows the user to inspect WebSocket (WS) traffic. In other words, the user is able to see data (payload) of all WS frames sent or recieved. This can be done in the
Messages side panel.
Data sent through WS frames are often using custom format. It can be plain text, JSON, or more sophisticated protocols for Socket.IO, SockJS or SignalR. We want to make the inspection feature even better for these specific protocols, by parsing the data (sent through WS frames) and displaying them as expandable tree.
We already supports those protocols (i.e. we already have parsers for the above protocols) and this bug is about
supporting a new one for: Action Cable
So, to support a new protocol, we need to introduce a new parser. In this bug we need to introduce a parser for Action Cable WS frame payload.
There is great information about the protocol (for Action Cable) in comment #1 and there are some existing instructions showing how to integrate new parsers with the existing infrastructure here: https://bugzilla.mozilla.org/show_bug.cgi?id=1589068#c2 <- this link points to a bug that was about supporting SignalR, it's already fixed. But, the instructions are useful in this bug too.
I was looking at this bug scope again and it might be more complex and doesn't feel as ideal good first bug. You might want to look around for other first-good-bugs and get some more experience first. I see that you are already assigned to another two bugs so, what about fixing them first?