Question on Data Sheet for targets

Newbie here. I am trying to make sense of the target Datasheet - specifically the sub-class of the target. Is there a legend for what the letters and numbers mean?

For example - NGC7380 has a data sheet showing a sub class of III3pn. What does this mean?

As a newbie I am trying to work out what images with RGB and what needs more specialised filters - HA, OIII etc. I was hoping the sub-class may give me a hint. Didn’t want to spend time imaging something that needs a set of filters I don’t own…

Thanks for any advice.