[rpdillon]

The license doesn't indicate that you can get out of the terms by developing your own map editor. A map editor would qualify as a game engine product because it can edit game content and their license specifically prohibits you from redistributing a game engine product that's built with Defold.

[Tepix]

Here's what the license states:

    You do not sell or otherwise commercialise the Work or Derivative Works as a Game Engine Product.

    "Work" shall mean the work of authorship, whether in Source or Object form,
    made available under the License, as indicated by a copyright notice that is
    included in or attached to the work

    "Derivative Works" shall mean any work, whether in Source or Object form, that
    is based on (or derived from) the Work and for which the editorial revisions,
    annotations, elaborations, or other modifications represent, as a whole, an
    original work of authorship. For the purposes of this License, Derivative Works
    shall not include works that remain
    separable from, or merely link (or bind by name) to the interfaces of, the Work
    and Derivative Works thereof.

If you write your own map editor, it's neither Work nor a Derivative Works so this restriction doesn't apply.

[rpdillon]

Thank you, after re-reading, I agree.

[mst]

If the map editor is an extension (and they have lots of example extensions on github, all of which I've checked are under normal open source licenses) rather than a set of patches to the core code itself, it isn't subject to the Defold License in the first place.

(so if the extension API is missing something, contribute the feature(s) you need back to core, then you can write your extension free of issues, so far as I can tell)