If you want to build a custom dartstracker and exploit it commercially a commercial license can be acquired from the webshop that opens up the API's and interfaces for custom integration.
Otherwise the following Personal Use License is granted.
The content owner grants the user a non-exclusive, perpetual, personal use
license to view, download, display, and copy the content, subject to the
following restrictions:
The content is licensed for personal use only, not commercial use. The
content may not be used in any way whatsoever in which you charge money,
collect fees, or receive any form of remuneration. The content may not be
resold, relicensed, sub-licensed, rented, leased, or used in advertising.
Title and ownership, and all rights now and in the future, of and for the
content remain exclusively with the content owner.
There are no warranties, express or implied. The content is provided 'as
is.'
Neither the content owner, payment processing service, nor hosting service
will be liable for any third party claims or incidental, consequential, or
other damages arising out of this license or the buyer's use of the content.