They had a massive segment of military goods for sale. Everything from drone supplies to body armor. So they are actively engaged in supporting the Russians invasion.

These are also massive warehouse hubs for the distribution of all sorts of goods. Like a large Amazon warehouse. Destroying them is an absolutely massive hit to the Russian economy with minimal risk of civilian casualties.

Am I correct in my understanding that Ukraine is targeting Wildberries because they were distributing parts used to manufacturer drones for warfare?

They sell all kinds of wares that help murder Ukrainians.

Russians signing up for the military need to get their own equipment since quite some time.

Same with Wildberries competitor Ozon:

They also distributed general military gear you could purchase from them. But yes this is logistics being hit, not manufacturing.

They had a Special Military Operation section where anyone could ship your favorite pre-ground meat some helmets or whatever.

That might be part of it, but they're one of the largest debtors in russia, with billions owes to banks.

Their bankruptcy will cause a cascading effect with banks failing. Classic case of "if I owe the bank a thousand dollars, that's my problem, if I owe them a million, that's their problem". There are already signs that russian banks are facing insolvency issues.

Ukraine is targeting the weak points of russia, the parts which will deal the most damage to economy. Wilberries happens to be one of this points as majority of russians are using it for buying products, and manufacturers use it to sell products. It is a huge multi-billion logistics company, which when destroyed will cause irreparble damage to economy. Yesterday it was oil refineries, today wilberries, tomorrow something else.

With drone parts it’d be more effective to hit where they’re coming from if that’s domestic production.

So in my understanding it’s an economic damage measure - warehouses for a marketplace where businesses sell all kinds of stuff. And since it’s the biggest one like that in Russia - it hurts them a lot, which is nice.