How do I fork a git tool and edit it for use with another DVCS, without confusing git users?

Question

I'm not a git user (gasp). I use darcs. My question is: What steps should I take to fork a git repo, host it on github, yet make it apparent that it is to be used with a darcs repo? I'm trying to port an Atom package (git-time-machine which depends on git-log-utils) to make it work with darcs. I want to reuse most of the Javascript in both of those projects and just rewrite some of the bash commands and rewrite the parsing methods that handle what those commands return. Everything else should be reusable as far as I can see. I don't want my fork(s) to confuse people though. Is there a convention I should follow?

Loose example of something I want to replace (line: 1):

    cmd = "git log" + flags + " " + fileName;
    if (process.env.DEBUG === '1') {
      console.log('$ ' + cmd);
    }
    return ChildProcess.execSync(cmd, {
      stdio: 'pipe',
      cwd: directory
    }).toString();

with (this code WILL NOT work, it's a loose example):

    cmd = "darcs annotate" + flags + " " + fileName;
    if (process.env.DEBUG === '1') {
      console.log('$ ' + cmd);
    }
    return ChildProcess.execSync(cmd, {
      stdio: 'pipe',
      cwd: directory
    }).toString();