not getting content names

[Jean Louis]

mail -s Hello -E "set sendmail=\"sendmail:/home/admin/bin/sendmail\"" 
--alternative --content-name HTML --content-type=text/html -A 
/dev/shm/html-file --content-name TEXT --content-type=text/plain ss@example.com 
< text

I have noticed that I do not get content-name set by using above
command.

I am using mail (GNU Mailutils) 3.7.90-2
[release-3.7-5-gbd46cf8d4-dirty]

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