Should parse() or escape() always be used? When should text() ever be used?

Basic documentation is here: https://www.mediawiki.org/wiki/Manual:Messages_API#Output_modes_and_escaping. text() is for situations that don't need escaping, e.g. when the output goes to a text file or console. It's most often used together with the Html class. These lines are all correct and all do (mostly) the same:

$html .= Html::element( 'span', [], $msg->text() );
$html .= Html::rawElement( 'span', [], $msg->escaped() );
$html .= '<span>' . $msg->escaped() . '</span>';
$html .= '<span>' . htmlspecialchars( $msg->text() ) . '</span>';

The very first one is actually the recommended one.

parse() should be very rarely used because it's significantly slower. Only when you need the full power of wikitext.

@thiemowmde - thanks for finding these, and sorry for the long delay in handling this. I just checked in this fix - I don't know if I got all the necessary escaping there, but hopefully I got most of it:

https://gerrit.wikimedia.org/r/c/mediawiki/extensions/Cargo/+/899598