Please describe the problem.

The new --preserve-filename option does not have its described effect on torrent files.

What steps will reproduce the problem?

$ git annex addurl --preserve-filename \

(cancelling when at least a file has arrived)

$ tree
└── downloads.endor.at_chaos-math_multi-language_1080p_mkv.ea15601881aa1be1.torrent/
    └── 01._Motion_and_determinism_-_Panta_Rhei__1080p_.mkv 
$ btcheck -l <(curl '')
Base directory : chaos-math_multi-language_1080p_mkv
01. Motion and determinism - Panta Rhei [1080p].mkv     (409315188)

Based on the description of --preserve-filename, given that nothing in the names is particularly malicious, I'd have expected the tree output to look like this:

$ tree
└── chaos-math_multi-language_1080p_mkv/   (as per base directory)
    └── 01. Motion and determinism - Panta Rhei [1080p].mkv 

What version of git-annex are you using? On what operating system?

8.20200522 (built using gbp buildpackage from current git master, 87dc9cd0)

Please provide any additional information below.

This option, when working with torrents, would be a building block to bittorrent: support offline operation and verification, and resolve most of the suggestions from there.

Have you had any luck using git-annex before?

Yes: It saved me from potential data loss when my backup cron jobs stopped working and the mails got lost -- git annex drop failing on the laptops was both the right thing to do given numcopies=2, and alerted me to the problem in due time.