The man page suggests passing '-v' (lower case v) to Thunar in order to see its version number. In reality the option is '-V' (upper case v).
Created attachment 8501 Proposed documentation patch
Joel Matthews referenced this bugreport in commit be517354eb8fa4c4d9eef59033ec2a767bf3c00d man page incorrectly suggests '-v' instead of '-V' (Bug #15374) https://git.xfce.org/xfce/thunar/commit?id=be517354eb8fa4c4d9eef59033ec2a767bf3c00d
Joel Matthews referenced this bugreport in commit 987045534e2c4cbd1ad0b31d0cd37d393a499a3c man page incorrectly suggests '-v' instead of '-V' (Bug #15374) https://git.xfce.org/xfce/thunar/commit?id=987045534e2c4cbd1ad0b31d0cd37d393a499a3c
Thanks for the patch ! Fixed now for master and 4.14 branch