Is there a precise license on this pack?
Yes - here are the details for this asset packs license
License Things you can do -
This license grants you, the purchaser, an ongoing, non-exclusive commercial, worldwide license to make use of the Item (game asset) you have selected to make games, or interactive content. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission. The project assets are as is and makes no warranties about the work, and disclaims liability for all uses of the work, to the fullest extent permitted by applicable law.
Things you can’t do -
You can’t re-distribute the Item as a game asset, as stock, in a tool or template, or with source files. You can’t do this with an Item either on its own or bundled with other items (such as an asset pack , or collection of item), and even if you modify the Item. You can’t re-distribute the Item as-is or with superficial modifications. These things are not allowed even if the re-distribution is for free.