Override YAML on a screen edits <name>.local.yaml, a package loaded after
the shared board package. New profiles get an empty one; an existing
profile is attached on the first save without reformatting the file. The
editor validates YAML, refuses the managed sections and substitutions,
and Save & check runs ESPHome's full validation of the complete profile.
The example uses !extend: ESPHome appends package lists instead of
merging them by id, so a bare id added a second display without a
platform and failed the build. An override is 12 KB at most and a
too-large body answers as JSON instead of a bare 413. The sidecar is
written before the profile includes it, and a symlinked sidecar is
refused. Firmware stays 0.2.52.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Max Gramser