Remmina - The GTK+ Remote Desktop Client  v1.4.1
Remmina is a remote desktop client written in GTK+, aiming to be useful for system administrators and travellers, who need to work with lots of remote computers in front of either large monitors or tiny netbooks. Remmina supports multiple network protocols in an integrated and consistent user interface. Currently RDP, VNC, NX, XDMCP and SSH are supported.
Update-gettext-messages

This is a quick, dirty and no brainy procedure to update the po files in Remmina.

Please count till 10 seconds before to copy&paste it in the terminal.

REMMINATOP=~/remmina_devel/Remmina
cd $REMMINATOP
find src plugins -name "*.c" | sed 's/^.\///' >| po/POTFILES.in
find data -name "*.glade" | sed 's/^.\///' >> po/POTFILES.in
find data -name "*.appdata.xml" | sed 's/^.\///' >> po/POTFILES.in
xgettext --from-code=UTF-8 -k_ -kN_ -ktranslatable --keyword=C_:1c,2 --keyword=NC_:1c,2 --keyword=g_dngettext:2,3 --add-comments --files-from=po/POTFILES.in --output=po/messages.pot --copyright-holder="2014-2018 Antenore Gatta, Giovanni Panozzo" --package-name="Remmina" --package-version="1.2.31" --msgid-bugs-address="admin@remmina.org"
cd $REMMINATOP/po
for i in *.po; do
msgmerge -N --backup=off --update $i messages.pot
done
for i in $REMMINATOP/po/*.po ; do
TMPF=/tmp/f$$.txt
sed '/^#~/d' $i > $TMPF
awk 'BEGIN{bl=0}/^$/{bl++;if(bl==1)print;else next}/^..*$/{bl=0;print}' $TMPF >| $i
rm $TMPF
done
rm *.po~
rm messages.pot

To test remmina in another language you can start it from the command line this way:

LANGUAGE=ru remmina