Subjects like FIction, JUvenile, HIstory ?

I've come across something that's either typos or some standard I haven't seen before.

Subjects like this:
ALgebras,
BIography
FIction
FOrecasting
HIstory
JUvenile
MUsik
SIsters

i.e. the first two letters are uppercase and the rest is lowercase. I was thinking that maybe it was meant as some sort of call number? I.e. printing JU on Juvenile books, FI on Fiction etc. Does that make sense?

(They occur in the Subjects field in my TSV export file, i.e. I don't really know where they come from.)

Are they all capitalised in this way? I have done similar typos occasionally, when one finger hits the next letter key before another finger has come off the shift key, but if every single subject is capitalized in the same manner, I have to assume it was intentional. A call number or some other sort of symbolising is the only reason I can think for something like this, but it's not something I've ever seen before, either.

>2 GraceCollection: There are all sorts of variations, so yeah typos are probably the explanation. A fun fact is that these mostly occur in the export file, i.e. when I notice stuff like Schools > FIction in the export file for Book_Id 22821938 and looks in my LT "Your books" catalog for it in a style where Subjects are included, it isn't displayed. So maybe it is just some kind of ghost, sorry GHost :-)

I just checked and all nine books with FIction in the TSV export file Subjects field show it as Fiction in the LT catalog. A bit weird, but not enough to report as a bug.

And is seems as there is both say Murder FIction and Murder Fiction so maybe what is shown in LT is run through a case insensitive sort where duplicates are discarded.

Note to self:

https://www.librarycat.org/lib/bnielsen/item/285345953

displays the Subjects as
ALgebras, Linear
Algebras, Linear Textbooks

so at least one of the subjects starting with two uppercase letters are visible in TinyCat.