The extractor of GDP ignores duplicate files in ZIP files. For example,
if running GDP on the archive from GOG
$ game-data-packager simon1 --no-download simon_the_sorcerer_en_gog_1_19763.sh
[...]
ERROR:game_data_packager.build:simon_the_sorcerer_en_gog_1_19763.sh should have provided 0032.vga but did not
ERROR:game_data_packager.build:simon_the_sorcerer_en_gog_1_19763.sh should have provided 1522.vga but did not
ERROR:game_data_packager.build:simon_the_sorcerer_en_gog_1_19763.sh should have provided sfxxxx18 but did not
ERROR:game_data_packager.build:simon_the_sorcerer_en_gog_1_19763.sh should have provided sfxxxx19 but did not
However if I manually unzip the archive, GDP correctly finds these
files.