Where does “включений” come from?

включений (Ukrainian) comes from Ukrainian -ений, from Russian -ёный, from Old East Slavic -енъ, from Proto-Slavic -ěnъ — Forming adjectives meaning 'made of '; -en.

Ancestry of “включений”, step by step

StepLanguageWordMeaning
1Ukrainian-енийUsed to form passive participles from imperfective and perfective verbs
2Russian-ёныйSuffix used to form passive-participle-like...
3Old East Slavic-енъ—
4Proto-Slavic-ěnъForming adjectives meaning 'made of '; -en
Every word from Proto-Slavic -ěnъ →Every word from Ukrainian -ений →Every word from Russian -ёный →