Decompile SWF version 11

[lolbas]

The game in question is made by Gameloft, and the compiled SWF seem to be of version 11. The are a lot of UI's made of SWF, but they all seem to use library.swf and mainUI.swf files. The final goal I have in mind is to write my own UI but making it working as if it was the original. From what I understand, SWF files call game methods via some API, and I believe I can see the names in SWF file, but I'm not certain. I tried JPEXS Decompiler, but I don't have "Scripts" tree node in the result. Searching through the web only gives me very old results for old Flash version. Are there any up-to-date tools that can help me? Or what do I need to do/to research to achieve my goal?

Sample files: https://www.mediafire.com/file/y4qyxhfk6279ksx

[lolbas]

Alright, so deciding to look into this again after a break, I was able to parse the SWF with swf-parser lib, as well as 010 Editor SWF template from their repository, which turned out to have a bug that prevented me from parsing it at the time of the first post.

Anyway, I was hoping to see the byte-code (ABC) somewhere in the SWF tags, but the samples I checked don't have it. Instead, they have a tag of type = 300, which contains a lot of binary data (see screenshot). Googling the first bytes seem to reveal that this tag should actually be a byte-code, however
if I use a disassembler tool like Flazzy, it errors at runtime because either the code is invalid ABC, or it has some unsupported format. Any suggestions?

[lolbas]

So this turned out to be the byte-code, however with the help of Flazzy I was able to figure out

At 0x12 you can see that there are 5 params, and 0x1b tells us that 7 of them are optional, which is totally nonsense because

...The number of optional parameters is given by option_count, which must not be zero nor greater than the parameter_count...

(from official documentation, par. 4.5.1).

Attached screenshot shows the method infos block (0x0 byte indicates methods count). Any ideas what's actually going on here?