> JWST looked at TRAPPIST-1 in mid-infrared wavelengths of light — 20 times redder than the human eye can see
What's referred to here, in terms of wavelengths, is the range 4.9 to 27.9 μm according to https://jwst-docs.stsci.edu/jwst-mid-infrared-instrument. The longest human eyes can see is around 0.75 μm, so I guess that's where the notion of "20 times redder" comes from