This ticket is for adding language codes for the representations of Rangpuri (also known as Rajbongshi) and Chittagonian lexemes and forms.
Q3241618 and Q33173 are the Wikidata items for these languoids (considered languages by some and dialects by others).
Note that both tags are assuming the use of the Bengali script; absent specimens of Devanagari text for the former and Arabic text for the latter, ISO 15924 subtags are not being asked for here.