Many people have and use these little LCD hygrometers.  I thought it would be nice to have a simple magnetic mount to put one inside my Elegoo Centauri Carbon.  I'm pretty sure this design will also work easily with other enclosed printers.

The frame of the holder is based on the hygrometer-holder.STL part from @GunplaMark's Ultimate Cereal Container Filament Drybox.  I'm not sure this qualifies as a remix becuase I'm only using that one part.  :D
(but, if it does count as a remix - I will happily correct this!) 

I printed this in ABS with a 0.4 nozzle and 0.2 layer height.  No supports are needed when oriented "face down".  The design uses two 10x2mm magnets to hold it in place inside the printer but, those could be adjusted if needed.  It could probably be printed ASA or even PETG but, keep in mind the temperatures in the printer chamber when selecting a filament, especially if you have a heater.  I would not recommend using PLA for this.

Note: this little display doesn't show through the tinted door very well when closed.  But, shining a light through the door does let you see the LCD display.