It seems old posts just get ignored and lost so posting again hopefully someone at hubspot can fix their awful 30 second+ page load times:
Old thread:
https://community.hubspot.com/t5/CMS-Development/Hubspot-Developer-Documentation-Filters-Functions-page-broken/m-p/778311
At this point I think this has been an issue for at least 2 years
(I have 500Mbps broadband so that’s definitely not the issue)
Hey, @matt_scott 
The dev advocate team informed me they rolled out a fix for this today. Just after you posted this. Can you try again? If it’s still laggy, try clearing your cache.
It’s loading up for me much faster now.
Best,
Jaycee
This is such a relief… Thank you for fixing that…
I know that a lot of folks pointed this out for such a long time… My tab/browser was freezing everytime I wanted to open this page…
After many long years of waiting for a fix for waiting for the page it finally happened, I’m obviously greatful but also exasbated at how long this thing took, (I imagine it took someone 10mins to fix)