Thanks for pointing this out @FichteFoll. This is the first package I've created, so I'm not sure which route to take.
On the one hand, I would think that targetting ST3 is better because it would make maintainance easier for me. On the other hand, the package is rather simple and doesn't require ST3 specific features, so somehow I regret that ST2 users won't be able to use it.
I have no idea how I could make a package work for both ST3 and ST3 while still keepig ST3 formats for ST3, I'm still going through the various documentation but I haven't found anything on the topic.
Also, I have a ST3 license only, and I'm not sure it allows me to keep also a copy of ST2 (the licenses are different).
What would be your advice, based on experience? The syntax I'm creating targets a very small audience, and I don't think that many users will install it anyway.