Tell the user when the site was deployed again since their page was loaded: its scripts and views are then those of the old release, and only a reload brings the new ones.
MMO.release = {…}
Namespace
MMO
The server says its release in `X-App-Version` on every response, and the one the page was built with in
`MMO.config.release` (`Theme::getRelease``). No call of its own: every `fetch()` of the page --
`MMO.fetch`, the `APIRequester`s, all of them go through it -- is looked at as it comes back, and the first one
whose release is not the page's shows a notification offering to reload. It never reloads by itself: a form may
be half filled. A theme with `releaseCheck: false` sends neither, and nothing is ever shown.