html/template rewrites an href whose scheme it does not recognise to
"#ZgotmplZ". echolot:// is not on its list, so "Open in the Echolot app"
was not a link at all — tapping it did nothing, and nothing showed it:
the markup reads correctly, the app resolves the scheme, and only the
sanitised attribute in the served HTML gives it away.
Marking the value template.URL opts out of that sanitising, which is only
safe because the shape is now checked first. The link arrives in a query
parameter, so without the check a crafted /devices?link=javascript:… would
put a script URL into the page for an admin to click.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
