The two conflicts are both places where upstream landed on top of IDEX/IQEX
code. In GCode.cpp the relocated file header block meets the IMEX placeholder
block, and the placeholders are set first: file_start_gcode is processed through
the placeholder parser now, which throws on a name it does not know, so a script
naming {imex_mode} would abort the export if the header ran first. In
test_multifilament.cpp both sides appended a case at the end of the file.