Ryanair's new policies (in force since November 2018) allow only one "small bag" for passenger (unless he purchases priority or other extras).
However, I'm confused about its sizes. The official statement (here and here) says:
We have increased the size of the free small carry-on bag by over 40% from 35 x 20 x 20cm (14,000 cm³) to 40 x 20 x 25cm (20,000 cm³).
We have almost doubled the size of our small bag sizer from 35 x 20 x 20cm (14,000 cm³) to 42 x 20 x 30 cm (25,200 cm³) to allow carry-on bags that are considerably (25%) larger than our permitted small bag dimensions. (See diagram)
I couldn't find the answer to the simple, obvious question ensuing: can I bring a bag sized 42x20x30cm? Such a bag would fit the sizer but exceed the allowance. Why do they give two maximum sizes? Which one is the actual one? Gosh, seems like they just want to lure customers into making mistakes.