Original mix, extended mix, bootleg, radio edit: What are these called - versions of audio products?
An original mix is the first version released of a work.
A bootleg is an unofficial version that is not sanctioned by the original creators and/or a publisher. One example of a bootleg version is recording a live performance and releasing that.
An extended mix is a longer version of a work. Sections can be repeated, new material in the style of the original can be added, and more. Even loops can be extended--in this case, the length of the material before the repeat is increased.
A radio edit is a shorter version of a work. It's generally cut down so more radio stations will accept it, and sections tend to be selected to appeal to more general listeners. Fun fact--the most famous version of Darude's Sandstorm is a radio edit!
The original mix is the version which is first released. It typically has all the required elements of the song as performed or assembled. Sometimes it does not as that can come across formatting difficulties, especially when it comes down to cutting vinyl or using CDs. Original mixes tend to have a broad scope of length and can be anywhere from a few seconds long to 15 minutes long. It is simply how the track was released.
A bootleg is any unsanctioned release. This can refer to releases where the track has been pirated before release, or even pirated after release. This can also refer to surreptitious recordings done at live recordings. This latter case has some interesting stories with regards to many songs so as a result, these can be very desired. A classic story is perhaps with Guess Who's American Woman which was originally performed as a live improv. A surreptitious recording of the set captured that live improv. This bootleg is out there but it was also shown to the band who later polished it up for a formal release.
An extended mix is a version explicitly made for discos. There are various definitions used with styles. A simple extended mix will have the a song 3:30 long taken to 7:00 long, where they might loop things over, do structural loop changes (filtering, delay) or they might insert related instrumental work that was either cut from the original mix or from some other recordings altogether (sampling.) Maxi mixes also exist which seem explicitly designed for DJs to take a bathroom break or to get a drink from the bar, such as this version of Blue Monday.
Radio Edits are edits designed for the rather strict format for radio. Radio broadcasting is built entirely around the original singles lengths of 2:30. You will notice on very old recordings from the 1950s that the songs never go longer than that. Songs edited down to this length will be called a Radio Edit, although they might get longer - up to a maximum of 3:30. But that is stretching it.