These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.06 s (backtrack: 0/20).

[ebuild  N     ] acct-group/dovecot-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-group/dovenull-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/dovecot-0-r3::gentoo  0 KiB
[ebuild  N     ] acct-user/dovenull-0-r3::gentoo  0 KiB
[ebuild  N     ] net-mail/dovecot-2.3.21.1-r1:0/2.3.21.1::gentoo  USE="pam sqlite -argon2 -caps -doc -kerberos -ldap -lua -lucene -lz4 -managesieve -mysql -postgres -rpc (-selinux) -sieve -solr -static-libs -stemmer -suid (-systemd) -tcpd -textcat -unwind -zstd" LUA_SINGLE_TARGET="lua5-1 -lua5-3" 7659 KiB

Total: 5 packages (5 new), Size of downloads: 7659 KiB