Remove incorrect (i.e.) all usage of seriesTitle which for journal articles refers to a collection of articles in a specific issue. This is not supported in BibLaTeX. Discussion of these confusing field: https://forums.zotero.org/discussion/18322/
Fix incorrect naming of zotero's abstractNote as abstract.
Add note at start of exported file. Remove some outdated comments about potential issues.
Use mvbook for books which have several volumes (non-empty "volume" field).
Use "annotation" instead of the alias "annote" in biblatex.
Enable meetingName to be written to "note". Let data outside biblatexdata[...] in extra field be written to note (unless meetingName is already written there).
Clean up writing of titles and publishers. Use "journaltitle" instead of "journal". Use "institution" instead of "school".