This package enables custom user interface when performing such actions like entering a passcode or selecting which level to teleport to.
Do note that this package require at least some ASM knowledge if you want to change the UI or add newer UI.
I'm regretful to inform that this resource, while potentially useful, is going to be rejected for now. The reasons are simple, but you may check into them:
The main issue is, in my opinion: you have to edit UberASMTool's internal code to make it work. I was not really thrilled when I discovered this little fact, going through your readme. For this specific instance, given the potential uses your resource has... why don't you use, for example, Layer 3? It's a small sacrifice considering your life with OAM issues would be significantly easier. See this as an example of what I'm saying.
Second: you said it requires a good amount of ASM knowledge in order to set up the UI codes. While not being a removal reason, I must ask you: why don't you, for example, give an instance code of the second feature (the level teleport menu), so the average user can easily see how it's done and then try to replicate it themselves? I think it'd be a nice thing to consider.
Last, but not least (and this is the final nail in the coffin, as to speak):
Tested in a SA-1 ROM and a LoROM. The result is shown above.
I strongly suggest you take a look into the user-friendliness of your resources, again. They're well thought, but you have to consider the insertion issues when submitting them to the asm sections. That being said, I hope you provide us a working version, without the bug I mentioned and without the need to edit the tool's base code.