It's called military intelligence, and yes of course that's what Ukraine does. Knowing how your enemy is armed and what specific advantages and weaknesses their equipment has can literally help to win a war. They'd be stupid not to inspect any remnants.
Ukraine also engages in a fair amount of propaganda (so much so that US and UK intelligence regularly contradict them), so asking for evidence isn't too unreasonable.
It's called military intelligence, and yes of course that's what Ukraine does. Knowing how your enemy is armed and what specific advantages and weaknesses their equipment has can literally help to win a war. They'd be stupid not to inspect any remnants.
Ukraine also engages in a fair amount of propaganda (so much so that US and UK intelligence regularly contradict them), so asking for evidence isn't too unreasonable.