These are out of date now and potentially misleading.
Adds a new error page for HTTP `410 GONE`. Looks like the 404 page, but
returns the appropriate error code to be a good web citizen.
I was using the trial mode page to prototype the time picker as part of
225a61ddd3.
I didn’t clean up properly, and left an errant undefined variable, which
caused the trial mode page to `500`.
This commit:
- removes the errant argument
- adds a test for all the static pages to make sure that they at least
return a `200`
