It must be escaped in "Only the last 20% of the indicator is displayed." because making mo files become impossible.

Index: locale/ru/LC_MESSAGES/frontend.po
===================================================================
— locale/ru/LC_MESSAGES/frontend.po (revision 27542)
+++ locale/ru/LC_MESSAGES/frontend.po (working copy)
@@ -8596,7 +8596,7 @@
#: include/services.inc.php:287
#, php-format
msgid "Only the last 20% of the indicator is displayed."
-msgstr ""
+msgstr "????????? ?????????? ?????? ????????? 20%."

#: include/blocks.inc.php:695
msgid "Only triggers assigned to enabled hosts and depending on enabled items are counted"

and if i trying to make mo files:
./locale/make_mo.sh
./locale/ru/LC_MESSAGES/frontend.po:8599: 'msgstr' is not a valid PHP format string, unlike 'msgid'. Reason: In the directive number 1, the character '.' is not a valid conversion specifier.
msgfmt: found 1 fatal error