I was looking the repository https://github.com/ladislav-zezula/StormLib and it's using the MIT license, so far so good.
However, looking at the following file https://github.com/ladislav-zezula/StormLib/blob/master/src/pklib/explode.c
static char Copyright = "PKWARE Data Compression Library for Win32\r\n" "Copyright 1989-1995 PKWARE Inc. All Rights Reserved\r\n" "Patent No. 5,051,745\r\n" "PKWARE Data Compression Library Reg. U.S. Pat. and Tm. Off.\r\n" "Version 1.11\r\n";
It seems to be using a compression algorithm that is patented. It probably was obtained using reverse engineering techniques.
Can I use StormLib? Can I use PKLib? Neither?
Apparently the term for patents is 20 years, so I'm good?