.dl Files Help

[reptilegpt]

Ok well the good news is i spent a good 5 hours making an animal for ZT2 (i wont say what the animal is yet)

Anyway everything is all set with that, its in a .z2f file all ready to go. What i need help with is the .dl file that goes along with downloaded content, how does that work? How do i open/make one? ect.
Basically I don't know anything what so ever about the .dl file so everybody gimme all that you know.  Thanks. Greg

p.s. i'll be sure to post a link for my animal as soon as its all set