[gentoo-user] Determine cause of xorg-server downgrade?

[Grant Edwards]

How do you determine the cause of a downgrade?

Today I did "emerge --sync" and "emerge -auvNDt world" with (I think)
no configuration changes since the last update a couple days ago, and
now emerge wants to downgrade xorg-server from 1.20.9 to 1.20.8-r1:

  Calculating dependencies... done!
  [ebuild  rR    ] x11-drivers/xf86-video-intel-2.99.917_p20200515::gentoo  USE="dri sna udev uxa xvmc -debug -tools" 0 KiB
  [ebuild     U  ] www-client/google-chrome-85.0.4183.83::gentoo [84.0.4147.135::gentoo] USE="(-selinux)" L10N="am ar bg bn ca cs da de el en-GB es es-419 et fa fi fil fr gu he hi hr hu id it ja kn ko lt lv ml mr ms nb nl pl pt-BR pt-PT ro ru sk sl sr sv sw ta te th tr uk vi zh-CN zh-TW" 31,175 KiB
  [ebuild  rR    ] x11-drivers/xf86-input-synaptics-1.9.1::gentoo  0 KiB
  [ebuild  rR    ] x11-drivers/xf86-input-libinput-0.30.0::gentoo  0 KiB
  [ebuild  r  UD ]  x11-base/xorg-server-1.20.8-r1:0/1.20.8::gentoo [1.20.9:0/1.20.9::gentoo] USE="elogind ipv6 (libglvnd) udev xorg -debug -dmx -doc -kdrive -libressl -minimal (-selinux) -static-libs -suid -systemd -unwind -wayland -xcsecurity -xephyr -xnest -xvfb" 0 KiB

  Total: 5 packages (1 upgrade, 1 downgrade, 3 reinstalls), Size of downloads: 31,175 KiB

AFAICT both 1.20.9 and 1.20.8-r1 are stable on amd4 (the only
difference between the two .ebuild files are the keywords for hppa and
ppc).  I can't find any ebuilds that appear to depend on the
downgraded version.

--
Grant