HTML xpath verification api documentation

I'm building b2c marketplace like etsy on solana.
I would like to provide proof of sending by DPD, but dpd has no any public api for such cases.
I've read in https://medium.com/zkpass/monthly-technical-updates-june-2024-aa98b884b5bd that you have implemented xpath verification not long time ago :) 
Can I ask for some documentation or maybe where I can find api methods.

Thank you!