I am working for an office-add-in for PowerPoint. I need to assign some unique identifier to my files, so that files can be identified in any dot net application. I did similar work for Word using custom properties. But for PowerPoint there is no way to read/ write custom property using office.js.
The only way I found using tags:
<https://learn.microsoft.com/en-us/office/dev/add-ins/powerpoint/tagging-presentations-slides-shapes>

but when I add tags to the presentation, I am not able to see those tags in presentation directly, I am able to read/ write through code only. Also I am not getting a way to read these tags from dot net application.

Any help will be great.

I am storing my files to azure blob. And reading files in my dot net core application to identify whether it has been saved from an office-add in or not. I am using syncfusion library in dot net core application to work with files.