A first launch that cannot reach the APK provider only ever showed
"Mocktail could not update or verify the Roblox installation.", while the
actual cause stayed in the session log. For a user that is
indistinguishable between a provider outage, a rejected signature, and a
full disk.
Name the host in HTTP transfer failures, so "HTTPS request returned status
503" becomes "api.pureapk.com request returned status 503", and relay the
updater child's stderr through the launcher: every line still reaches the
session log, and the last failure it reported is now attached to the
preflight result. The failure dialog shows that reason and the session log
directory instead of the generic sentence.
LightZirconite