Happy new year! I'm glad you are adding more customization. 1. Why is the standard value of bibtex-BibTeX-aux-entry-alist given as '(("Conference" "Article in Conference Proceedings" "InProceedings")) ? 2. I still don't understand the point of making a distinction between "dialects". As I've tried to emphasize before, which fields are accepted is under the purview of the bst (for bibtex) or bbx/cbx/lbx file (for biber+biblatex) that the user will eventually use. That can't be inferred from the contents of a .bib file; in fact, a .bib file could be used in multiple different projects with different bst/bbx/cbx/lbx files, all of which allow for different fields. I still maintain that the best approach is to be permissive about *parsing* entries in bibtex-parse-entry. That is a different question from the contents of templates provided by C-c C-e [KEY], for which of course the mode must know about the structure of each given entry.

Best

Leo