The string "%%" is hard coded here as a date prefix: https://code.orgmode.org/bzg/org-mode/src/master/lisp/org-agenda.el#L5648
Shouldn’t this be diary-sexp-entry-symbol to allow local overrides, etc.? -- Dr Joseph A. Corneli (https://github.com/holtzermann17) HYPERREAL ENTERPRISES LTD is a private company limited by shares, incorporated 25th, June 2019 as Company Number 634284 on the Register of Companies for Scotland (https://beta.companieshouse.gov.uk/company/SC634284).
