When loading on LispWorks 6.1 x86 on Windows I get
Error: Error while trying to load definition for system jonathan from pathname C:\Users\zulu\quicklisp\dists\quicklisp\software\jonathan-20190202-git\jonathan.asd:
External format (:UTF-8 :EOL-STYLE :LF) got error reading #<STREAM::EF-FILE-STREAM C:\Users\zulu\quicklisp\dists\quicklisp\software\jonathan-20190202-git\README.md>: cannot convert #x2000B to a character as this exceeds the char-code-limit (#x10000).
Tracked this down to the system doing a read-time eval to load in the readme into its long-description:
When loading on LispWorks 6.1 x86 on Windows I get
Tracked this down to the system doing a read-time eval to load in the readme into its long-description: