Without further ado, the following was found:

Issue:    B<…>size_t n → B<…size_t> I<n>

msgid ""
"B<int mbtowc(>size_t n;\n"
"B<           wchar_t *restrict >I<pwc>B<, const char >I<s>B<[restrict >I<n>B<], size_t >I<n>B<);>\n"