Unique identifier for C++ Crashpad/Breakpad/Minidump

We’re using Sentry for our C++ app in combination with Crashpad.
It’s working fine so far but there’s something I just don’t understand and can’t find a solution to.

Our apps are used in the media industry and some users can’t take their production systems online. Hence I created a tool to collect the mini dump files on their system so they could send the crash logs from another system which is connected to the internet.

So now I have a folder full of crash logs. I can upload all of them through curl, but I just don’t understand how to find the relevant reports through Sentry after uploading.
Is there any kind of UUID within the mini dump files? Is the file name of the dump file taken into account? How do others solve this problem?

I tried adding a custom tag but it looks like it didn’t work since I couldn’t find it when I searched for it after uploading.

Any help is much appreciated!