Yeah, they're hidden away in their git repo [1]. They have a good set of example usage commands [2], and a nice introductory document explaining what dat is [3]. Perhaps most important are the technical notes [4] that describe the supported formats.

[1]: https://github.com/maxogden/dat

[2]: https://github.com/maxogden/dat/blob/master/usage.md

[3]: https://github.com/maxogden/dat/blob/master/what-is-dat.md

[4]: https://github.com/maxogden/dat/blob/master/notes.md

There is another readme that is more informative:

https://github.com/maxogden/dat/blob/master/what-is-dat.md