this can only be done on PC afaik, but its the same in all browsers I use (firefox, chrome, brave, opera)
1.open the chat with the model
2.right click anywhere on the page > Inspect
3. Go to the network tab
4. Find the latest one of this I highlighted element (i think its called?), these contain the messages you and the model are sending to eachother and as you scroll up and the chat refreshes with more messages you will get another one of these elements, but if its the latest message it will be the latest one
5. go to Preview, and click on "list:" to expand it, below are the messages contained in the ^above element, you can expand each of these messages to find the one you are looking for which contains the videos she tries to send you.
6. Expand the messages on by one and read the "Text:" (highlighted in green) to identify the correct message, once you find the correct message you expand "media:" and there is all the medias in that picture, and then "duration:" (highlighted in pink) is the duration in seconds of the video. The "id:" indicates when it was uploaded to onlyfans, this is abit more complicated and I dont have time to get into it right now but if the media ID starts with 359xxxxxxx it was uploaded in December 2024, I can tell the video this model sent me in my picture was uploaded to OnlyFans on March 30, 2023, I can tell this because the preview media ID is roughly the same as the media ID behind the paywall, and the preview you can tell exact date by checking last-modified in the header.
Ive been meaning to write a small guide about it for a while since you can avoid losing a lot of money by checking file info that creators trying to hide in bundles, but Im bad at getting my thumb out my ass.. I hope it cleared something up atleast.
一度きりの送信、二度とありません 
ファンのお気に入り：
これが「それ」だよ。