About your footnote: see Knuth's paper "The Errors of TeX", a detailed analysis of 860+ "errors" made during TeX's development. (https://yurichev.com/mirrors/kn

About your footnote: see Knuth's paper "The Errors of TeX", a detailed analysis of 860+ "errors" made during TeX's development. (https://yurichev.com/mirrors/knuth1989.pdf https://yurichev.com/mirrors/knuth1989.pdf or DOI: 10.1002/spe.4380190702) (The current number stands at 947: http://texdoc.net/texmf-dist/doc/generic/knuth/errata/errorlog.pdf http://texdoc.net/texmf-dist/doc/generic/knuth/errata/errorl...)