It appears I downloaded it from
https://99bitcoins.com/how-to-get-a-custom-bitcoin-address/vanitygen-0.22-win is the folder name after download.
I've only used it offline and have never had any btc stolen from it but I am genuinely curious if this is a trust vanity address generator.
I saw conflicting things online.
It may be this one ->
Vanitygen: Vanity bitcoin address generator/miner [v0.22]1. The one I've linked is the oldest and most reputed vanity generator I know.
2. Although I remember 99bitcoins as being a legit/ok website, I'd recommend you use the one linked from the bitcointalk thread.
3. There may be newer vanity generators that are better (maybe SegWit too?), but I didn't care about them after I've "met" the HD wallets.