What should never be translated

What is skipped already

WPGlotty leaves alone what would break if it did not: script and style contents, code blocks, attributes that are not text, and anything inside an element marked with the standard translate="no" or the notranslate class.

Your own exclusions

Translations → Exclusions takes CSS selectors and exact strings. A selector protects everything inside it: a widget, a form, an embedded booking system. An exact string protects that text wherever it appears.

Selectors are the better tool. A string exclusion is a blunt instrument that will eventually match something you did want translated.

Shortcodes and embeds

Shortcode output is translated like anything else, because by the time WPGlotty sees the page the shortcode has already run. That is usually what you want and occasionally not: a shortcode printing a licence key, an API response, a serialised blob.

Wrap those in an element you can name in the exclusions list, and they are safe.