Old bugs are sometimes undesirable to fix because other systems/users have come to rely on their behavior.

That's a weird take. Do you have an example tibbar?

	▲	tibbar 12 minutes ago \| parent [-]
		Sure. This one already came up. [0]. In general, for a system like Postgres, many bugs affect only "extreme edge case" scenarios, but fixing them might create severe performance issues or require changing or removing other important features. So it's better to not fix them. [0] https://www.postgresql.org/message-id/flat/c22286ad6268347c6...