Every proprietary contract behind a public service has an end date. What survives it depends on what the agency wrote down before signing: export rights, formats, schemas, and an exit plan. Real cases from Boston, Schleswig-Holstein and Munich, and what the law now says.
If a council pays for software, the council should be able to show it to anyone, and other councils should be able to use it. A plain-language case for publishing publicly funded code, the governments that already do, and the honest objections.
Someone is paying for the code public systems run on, or it's rotting. Two of the worst vulnerabilities of the decade, xz-utils and Log4Shell, came out of projects run by volunteers. Public data portals sit on the same stack, and almost nobody is counting what's underneath them.
A disclosure law ends at the ribbon-cutting. The public's right to know doesn't. Closed pipelines behind an "open" label, portals that publish without being usable, and public budgets that keep re-funding proprietary systems: three concrete failures, and three things Mir Labs does about them.