001 mentioned processors being written in STAGE2.
In particular, we could have a library of pre-written code in STAGE2, available for people to copy and use.
We could also provide pre-written code in COBOL, available for people to copy and use. I have never seen libraries of COBOL source code, available for use by a person writing in COBOL, where the user would use a Cobol command to include the code from the library. Nevertheless, similar things have often been done. (1) People look at existing pieces of code and include them manually by cut and paste. (2) Some program generators, e.g. UNISYS LINC, generate Cobol source code.
001 mentioned processors being written in STAGE2.