Hi,

return is OK with:
     mtxrun --script font --list --spec --filter="fontname=ibm*"

but removing the m from the pattern
mtxrun --script font --list --spec --filter="fontname=ib*"

I get :
lua error : function call: 
...0-app_context-linux-64/tex/texmf-linux-64/bin/mtxrun.lua:10080: bad 
argument #9 to 'format' (number expected, got string)


mtxrun --version
mtxrun          | ConTeXt TDS Runner Tool 1.32
mtxrun          | source path