*If it writes an empty .cdx file it means wbm doesn't have that.

Also, if it writes a non-empty file, that doesn't necessarily mean that wbm has it. For example, it might redirect to another URL but then doesn't have the URL that it redirects to.

Already saw some blank files:
>...:/z8/put/gd/from_desumlp_drive.google.com_search/0folder/1AowOdwFzlbRk0FVZsRGRYe2hyKhzo2h3_files_cdx$ ls -liahS
>[...]
>925805 -rw-rw-r-- 1 ubuntu ubuntu 0 Dec 6 22:28 16d1H92TaHGN6MxxDccawgjnOMRaJBjcl.cdx
>925960 -rw-rw-r-- 1 ubuntu ubuntu 0 Dec 6 22:29 19SVMJ1lGgzOf0PKTEEhcmyyjfwo6DDJC.cdx
>925954 -rw-rw-r-- 1 ubuntu ubuntu 0 Dec 6 22:29 1bypyGhaT_QuMJTyJOXxNvEBTUIZAs1G8.cdx
>925959 -rw-rw-r-- 1 ubuntu ubuntu 0 Dec 6 22:29 1cyHw1rliue2_83KeecMcKOLvhfF2F4oc.cdx
>925975 -rw-rw-r-- 1 ubuntu ubuntu 0 Dec 6 22:29 1DXCGEfDLva5d8tXdPjIkXiX2EHMwekIR.cdx
>[...]

Nevermind, those 5 Google Drive file IDs are all in wbm. Empty files due to connection refused or some other error. Picrel from
>https://web.archive.org/web/20210913104415/https://drive.google.com/uc?id=16d1H92TaHGN6MxxDccawgjnOMRaJBjcl
>= /z8/put/gd/from_desumlp_drive.google.com_search/0folder/1AowOdwFzlbRk0FVZsRGRYe2hyKhzo2h3/Anon Filly/IRL Filly/1559325186119.jpeg