This is a remix of Snap-together Icosahedron (d20) by aveday_ on Thingiverse: https://www.thingiverse.com/thing:2778943
I printed in PETG (Generic PETG preset) on my Prusa i3 MK3S+ using the .4mm nozzle and the 0.30mm DRAFT preset. The triangles snap together but leave a little gap in between each one. Printing with the 0.20 Quality preset made them snap together flush.
Designed to work with these flexible WS2812B LED strings: https://www.aliexpress.com/item/3256803643154784.html
Might work with other similar ones (affiliate links):
The author hasn't provided the model origin yet.