Nice! Are the early msdos versions basically the same?
Added: the comments in those files are better than nothing but they don't really say what the program is doing the way the original source code hopefully would. The labels are still the ones generated by the disassembler, so not very informative. Still, it's nice that someone did this and it's a good starting point for further study by anyone sufficiently motivated.
It discusses TP 3.0's operation, supposedly based on a disassembly. It's less interesting than it sounds (it's mostly a high level overview of how a small compiler works, rather than a real study of TP internals), but it helps.
You might also be interested by what appears to be a perfect decompilation (leaked source code?) of the IDE of Turbo Pascal 6.0 written in itself using Turbo Vision and the internal compiler/assembler/debugger : go to http://www.exmortis.narod.ru/index_eng.html in the "Compilers" section and search for "tpascal.zip"
Added: the comments in those files are better than nothing but they don't really say what the program is doing the way the original source code hopefully would. The labels are still the ones generated by the disassembler, so not very informative. Still, it's nice that someone did this and it's a good starting point for further study by anyone sufficiently motivated.
If of any interest, the source code to the BDS C compiler of the same era was released here: https://www.bdsoft.com/resources/bdsc.html