Oh right! I also went to the docs to check, but I misread :P
But I still don't understand the purpose of rgba() and rgbEx() with the values from 0-100. Not a single program I've ever used in my entire life did use 0-100 for setting RGB-colors. Except Construct. I guess it's easier to set something to 30% red, but that's such a specific thing I don't think I've ever needed that. Anyway, I'm glad there's still the variants that just take 0-255 values.
I wasn't going to go into detail, because it seemed a bit off topic, but since you are mentioning it...
The 0-255 range is a relic of the past which just refuses to die and it looks like it won't be dyeing any time soon.
The 0% to 100% range makes a lot more sense conceptually, 0% is no color and 100% is all the color, every position in the middle is valid. This allows the notation to represent essentially an infinite amount of colors, where with 0 to 255 you have a workable, but in comparison very limited amount of values, because there are no fractional values.
Using a single byte to represent a color channel was introduced at a time where using a 64 bit floating point value to do the same was impossible.
I guess the main reason it is still used, is for backwards compatibility. There are some really old file formats floating around and they are still supported, so that means that new programs still need to understand that color information can be stored in individual bytes.
You can also never underestimate the power of familiarity, there are a lot of people that will just not question that 255 is the maximum value a color channel can have. And so the range continues to be used. I am pretty sure that all popular image editing software uses the 0% - 100% range under the hood, but presents the legacy format in the UI.
In Construct there really is no reason to support the 0 - 255 range, other than backwards compatibility and user familiarity with the format. It literally offers no benefits.