Icon pack and license

I really like the icons Whimsical offers it’s users to put into wireframes.
Unfortunately, I was not able to find the information about what icon pack it provides or whether the icons are free for commercial use. Could you please give me a hand with this?
I am able to export the icons to pdf and use them in that form but I do not want to do violate any copyright.

Many thanks,

Hey Denis,

Our icons come from the wonderful icon library of Nucleo. Nucleo offers a collection of free icons and you can also buy a license for commercial use.

Here’s what their Copyright Notice says:

The Nucleo icons are copyrighted. Redistribution is not permitted. Use in source and binary forms, with or without modification, is permitted only if you possess a Nucleo icons license.