Has anybody heard of any of the following scales:
Gr6, It5, N6, Fr6, and Sw5?

If you have the slightest idea what they are, please tell me. I`ve seen it on the chord calculator on Musictheory.net, but I have no idea what they are, and curiosity has been bothering me. By the way, I used the calculator, and got the following chords for each chord symbol (in the key of C):

Gr6 - Ab, C, Eb, F#
It5 - Ab, C, F#
N6 - Db, F, Ab
Fr6 - Ab, C, D, F#
Sw5 - Ab, C, D#, F#

Please tell me what those symbols mean. Thanks.

Although I`ve never heard of this strange naming system, I can identify the chords based on the notes. As far as the names.... I have no clue, as I didn`t learn on this naming system.

The first one is a diminished seventh chord, taken from they A- key. All inversions of this chord form the diminshed seventh chord of another key.

The second is a first inversion F# diminished chord.
The third is the major chord of D flat major.
The fourth doeesn`t really have a standard name, however it can be called a dominant seventh chord with a flat five.

The fifth seems like a dominant seventh of D flat major with misnamed enharmonic equivalents for the D sharp and F sharp. D sharp being E flat and F sharp being G flat. Therefore A flat, C, E flat, G flat. Thats the dominant seventh cord of D flat major.

The full names for these are German 6th, Italian 6th (that 5 is wrong), Neapolitan 6th, French 6th and I don`t know the other one. The first three are built on chord IV- in C major, this would be F. You turn the chord into its 1st inversion (ie A C F) and flatten the bottom note and sharpen the top note, thus gving you the Italian 6th chord. For the German 6th, you add flat 3, ie Eb.l For the French 6th, you add scale degree 2, ie D. These are called augmented 6ths and move outward to chord V. (Ab-c-F#- G-B-D-G. The Neapolitan 6th is built on the flat 2 of the scale. Usually seen in 1st inversion. (ie in C major, Ab, Db, F). Called a 6th because of the interval between its top and bottom notes.

That Neapolitan 6th should be spelt F, Ab, Db. I am very tired and typed the 2nd inversion without thinking.
Also, I`m pretty sure that it moves to chord V, but not entirely certain on this.

Thanks for your responses, guys. Actually, I didn`t expect responses this quickly. I don`t have much time right now, so i didn`t really understand the explanation, but I`ll come back later to read it in detail.

Yeah, someone above is right.
French sixth, neopolitan sixth and so on.
This comes from grade 8 theory.

Read up on your Grade 8 Harmony guidebook.