Of these, 3,800 icons+ (4k apprx.) are completely free. They are free in the web app, free in the Figma file, free in the plugins,free on npm (almost everywhere).
Hope this helps.
For the pro license, am I able to build a tool that allows my users to search and select SVG icons to use in their webpages created in my app? My app is a website builder. I'd love to enable support for hugeicons. But maybe this is a gray area use case for the pro license?
For the use case you said, I see there's two possible way to use it,
1. Your users who are also Pro subscribers of Hugeicons can use their license keys to access and utilize Pro icons directly within your platform.
2. They only use free stroke icons from your platform.
The updated license agreement is this: https://hugeicons.com/license-agreement