By adding the '?' prefix, the app is searched by its name instead of its
package name (retrieving app names on the device may take some time):
scrcpy --start-app=?firefox
An app matches if its label starts with the given name,
case-insensitive.
If '+' is also passed to force-stop the app before starting, then the
prefixes must be in that order:
scrcpy --start-app=+?firefox
PR #5370 <https://github.com/Genymobile/scrcpy/pull/5370>