Roon has an extension programming interface (API = Application Programming Interface) to let third-parties extend Roon’s functionalities.
There is commercial hardware/software like rooExtend,
There’s RHEOS, a solution to output Roon to non-Roon Ready Denon/Marantz devices,
And there are many large and smaller community contributions like Apple TV Extension, alarm clock, hardware remote devices, alternative software control apps, etc. Many are discussed here:
and a (possibly partial) list is here:
They require separate installation - either on a Windows/Mac/Linux machine or (which is a typical solution) a separate little machine like a Raspberry Pi or one of the similar commercial devices like rooExtend.
If you have something like that, you might know. (Your computers/phone/tablet that run the official Roon app don’t fall into this category, nor do endpoints that are Roon Ready, Roon Tested / USB-attached or Chromecast/AirPlay.