there are a few hundred coders that have been involved in bitcoin protocol coding over the years.

and many many thousands that review the code and even adjust their copy of the code to do new things not based on the main protocol.

EG saving the UTXOset of their own local dataset into new database formats into different orders and or with extra info included for their own personal use of further analysis beyond the basics.

some add in extra API/RPC commands of their own to do extra communication things with their chosen peers

its ben deemed that to be a 'bitcoin coder' you need to be part of the elitist hierarchy allowed to make suggestions via the bitcoin core github commits.

where as those just reading, reviewing and tweaking their local copy of the code, not affecting the network rules. are just 'wallet coders'