Computer files. I am more familiar with them for miniature gaming. They are used with 3D printers using either FDM filament or others. Here,a link to HP site

https://www.hp.com/us-en/printers/3d-printers/materials.html?ps_us_go_mk_mc_cm016802_co_x_unb&gad_source=1&gclid=Cj0KCQiAst67BhCEARIsAKKdWOmIgSvOzYvLIkrQnMY_WN4xS7uWRm1V35V15WuEkqQhWH-uuqeFHQIaAqmpEALw_wcB&gclsrc=aw.ds

The fins on the drone bombs are a type of plastic