Launchpad currently recommends translating gtk+2.0 in Ubuntu Cosmic.

Template "gtk" in Ubuntu Cosmic package "gtk+2.0"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 862 862 0 0
Dakota 100.00  100.0% untranslated 862 862 0 0
Hawaiian 100.00  100.0% untranslated 862 862 0 0
Inuktitut 100.00  100.0% untranslated 862 862 0 0
Lakota 100.00  100.0% untranslated 862 862 0 0
Ojibwe 100.00  100.0% untranslated 862 862 0 0
Spanish 000.00  100.0% translated 0 0 6 6 2018-07-10 02:04:42 UTC 2018-07-10 Daniel Mustieles
Tlingit 100.00  100.0% untranslated 862 862 0 0
Yiddish 090.02  9.97679814385% translated  90.0232018561% untranslated 776 776 1 1 0 2018-07-10 01:54:41 UTC 2018-07-10 Raphael Finkel
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Template "gtk-properties" in Ubuntu Cosmic package "gtk+2.0"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 1729 1729 0 0
Dakota 100.00  100.0% untranslated 1729 1729 0 0
Hawaiian 100.00  100.0% untranslated 1729 1729 0 0
Inuktitut 100.00  100.0% untranslated 1729 1729 0 0
Lakota 100.00  100.0% untranslated 1729 1729 0 0
Ojibwe 100.00  100.0% untranslated 1729 1729 0 0
Spanish 000.00  100.0% translated 0 0 0 2018-07-10 01:48:05 UTC 2018-07-10 Jorge González
Tlingit 100.00  100.0% untranslated 1729 1729 0 0
Yiddish 056.22  43.7825332562% translated  56.2174667438% untranslated 972 972 0 0 2018-07-10 01:34:26 UTC 2018-07-10 Raphael Finkel
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Key to this table: “Unchanged” means Translated
and “untranslated” means just that, Untranslated

Other versions of gtk+2.0 in Ubuntu