Interesting question. Generally the problem is that TK sources are commercially licensed, so that leaves the following options for an open source project built on TK:
- Remove TK sources from distributions, pointing users to the TK store.
- Some form of volume licensing.
- Some form of revenue sharing (provided the OS project generates revenue in some way).
These options are usually counterproductive for most OS projects but maybe not yours.
Also, depending on what type of OS project it is and what version of TK is needed (for SpriteKit?) I could build a binary version specifically tailored to this specific OS project (with certain acceptable limitations, similar to the demo's binary framework). The main benefit being promotion of TilemapKit.
Can you be more specific as to what the OS project will be, its purpose (eg learning, promotion, master thesis), what engine/language it will be built with? Feel free to DM or email me if you prefer to discuss these details in private.