These are the third party libraries used by MuPDF.

Library Version Function License
Required:
freetype2.10.0 with patches Font scaling and rendering BSD-style
harfbuzz2.6.4 Text shaping MIT-style
libjpeg9.0 with patches JPEG decoding BSD-style
Incompatible fork of lcms22.9 with patchesColor management MIT-style
openjpeg2.6.4 with patches JPEG 2000 decoding BSD-style
zlib1.2.11Deflate compression zlib License
gumbo-parser0.10.1HTML5 parserApache 2.0
Optional:
FreeGLUT3.0.0 with patches OpenGL API for UIMIT-style
curl7.66.0 with patches HTTP data transfer MIT-style
JPEG-XR reference1.32 with patches JPEG-XR decoding special

NOTE: jbig2dec and MuJS are included in "thirdparty" but are copyright Artifex Software Inc.