In drawio source code, it looks like mxClient is only provided in minified format.
Where can I get drawio's mxClient.js unminifiend source code?
I tried to look up mxClient unminified version online but I only found V4.2.2 which is now deprecated.
The mxClient.js file relates to mxGraph with is End Of Life as of 2020-11-09. See the README of mxGraph repository.
The developers of draw.io continue to maintain their own private version of mxGraph and include it in draw.io. As it is a private version, they don't want the source code to be publicly available, so they don't (and probably won't) provide an unminified mxClient.js file.
What do you expect to find in this new mxGraph version?