Maybe before you get too boggled, consider that the original article is about a scientific instrument designed to be attached to a telescope. The aperture and focal length given in the other source are properties of the telescope, not the instrument.
Here's a page for another imaging device which lists the aperture and f-number of the telescope—and then gives a separate f-number for the instrument, without stating the instrument's aperture:
https://www.eso.org/sci/facilities/lasilla/instruments/wfi/o...
So I don't think the LSST media department dropped the ball on this one. The numbers (focal length and aperture), which you understandably think of as being essential info for any camera, just aren't as relevant here, partly because comparison with other options isn't in the forefront of the scientists minds (the camera is totally bespoke and there are many ways in which it is tailored to the telescope, which constrain its design, including in those two respects).
It's not uncommon to discuss CCD cameras for large telescopes without making any mention of the focal length or aperture of the telescope. See, for example: https://www.eso.org/public/teles-instr/lasilla/ntt/susi2/
Here's a page for another imaging device which lists the aperture and f-number of the telescope—and then gives a separate f-number for the instrument, without stating the instrument's aperture: https://www.eso.org/sci/facilities/lasilla/instruments/wfi/o...
So I don't think the LSST media department dropped the ball on this one. The numbers (focal length and aperture), which you understandably think of as being essential info for any camera, just aren't as relevant here, partly because comparison with other options isn't in the forefront of the scientists minds (the camera is totally bespoke and there are many ways in which it is tailored to the telescope, which constrain its design, including in those two respects).
Focal length and aperture of the LSST camera aren't mentioned here, either https://www.lsst.org/about/camera