Gregory's Servergit itself could be hacked someday soon to insert malicious code.
And compilers, text editors, etc.
Compilers that insert malicious code have been tested. If disassemblers and debuggers are also hacked, you'd never know.
A writer of SF once predicted computers which had normal memory for data and hardware-protected memory for code (both RAM and disks were segregated thusly.)
programmers and their specially-made code-writable computers were kept under lock and key and carefully monitored... like a printers and printing presses under Nazi Germany or USSR-controlled East Germany.
Obviously, networks were also forbidden to normal users.