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

Calculating dependencies ... done!
Dependency resolution took 1.50 s (backtrack: 0/20).

[ebuild     UD ] sys-apps/man-pages-6.10::gentoo [6.17-r1::gentoo] USE="-verify-sig" L10N="-cs -da -de -el -es -fi -fr -hu -id -it -ja -ko -mk -nb -nl -pl -pt-BR -ro -ru -sr -sv -uk -vi -zh-CN" 1840 KiB
[blocks B      ] <sys-apps/man-pages-6.16-r1 ("<sys-apps/man-pages-6.16-r1" is soft blocking sys-libs/libxcrypt-4.4.38-r1)

Total: 1 package (1 downgrade), Size of downloads: 1840 KiB
Conflict: 1 block (1 unsatisfied)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-apps/man-pages-6.10:0/0::gentoo, ebuild scheduled for merge) pulled in by
    =sys-apps/man-pages-6.10
    sys-apps/man-pages required by @system 

  (sys-libs/libxcrypt-4.4.38-r1:0/1::gentoo, installed) pulled in by
    sys-libs/libxcrypt[system(-),static-libs(-)?,abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?,abi_mips_n32(-)?,abi_mips_n64(-)?,abi_mips_o32(-)?,abi_s390_32(-)?,abi_s390_64(-)?] (sys-libs/libxcrypt[system(-),abi_x86_64(-)]) required by (virtual/libcrypt-2-r1:0/2::gentoo, installed) USE="-static-libs"
    sys-libs/libxcrypt[system] required by (sys-auth/pambase-20251104-r1:0/0::gentoo, installed) USE="nullok passwdqc yescrypt -caps -debug -elogind -gnome-keyring (-homed) -minimal -mktemp -pam_krb5 (-pam_ssh) -pwhistory -pwquality -securetty (-selinux) -sha512 -sssd (-systemd)"


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

https://wiki.gentoo.org/wiki/Handbook:X86/Working/Portage#Blocked_packages