I have updated SWI-Tinker. It now uses the WASM version compiled using the -DINSTALL_QLF=ON and -DINSTALL_PROLOG_SRC=OFF. That reduces the size of the data file from nearly 5Mb to 1.6Mb while it now also includes all of CHR rather than half of it. Starting the system and loading libraries is now way snappier 
That gave me the opportunity to add some more functionality, such as reusing the PceEmacs syntax highlighting to directly colour fragments in the editor, using more or less the same design as PceEmacs itself with Prolog closely connected to the editor.
I also added that the debugger now highlights the current line in the source code, so you have a traditional 4-port debugger, but with continuous access to the relevant source.
Enjoy!