how to get FlyBase ID conversion table
Indeed the web interface does not seem to link the full translation table, but it is available on their ftp server at releases -&gt; release_ID -&gt; precomputed_files -&gt; genes -&gt; fbgn_fbtr_fbpp_fb_2019_06.tsv.gz

For example, this is the latest (FB2019_06) translation table available.