Comment 3 for bug 1773463

I'd say the wildcard syntax is more common as it is described in a relevant RFC: https://tools.ietf.org/html/rfc4592#section-2.1.3
"
A wildcard "blocks itself" in the sense that a wildcard does not match its own subdomains. That is, "*.example." does not match all names in the "example." zone; it fails to match the names
   below "*.example."
"

~~

no-proxy=.domain.com
or no-proxy=*.domain.com
or no-proxy=.domain.com.
or no-proxy=*.domain.com.

will match:

domainhost1.domain.com
domainhost1.domain.com.
domainhost2.domain.com
domainhost2.domain.com.

but not

subhost.subdomain.domain.com
subhost.subdomain.domain.com.