[GNC] Custom field in GNUCash?

[flywire]

Standard Workarounds

Most users bypass this limitation by using strict data conventions in the
free-text fields:
* Description (Transaction level)
* Notes (Transaction level)
* Memo (Split level)

By embedding consistent text tags (like #ProjectABC or Client:JohnDoe) into
the Notes or Memo fields, you can use the Transaction Report Filter to
successfully isolate and sort your custom data lines. (Note: The Filter tab
only exists in the GnuCash Transaction Report).
If you need advanced data manipulation, you can also export your reports to
a spreadsheet program, or use the SQL backend format to run direct queries
in an external database.
Regards