Launchpad currently recommends translating gtk+3.0 in Ubuntu Artful.

Template "gtk-3.0" in Ubuntu Artful package "gtk+3.0"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 1361 1361 0 0
Dakota 100.00  100.0% untranslated 1361 1361 0 0
Hawaiian 100.00  100.0% untranslated 1361 1361 0 0
Inuktitut 100.00  100.0% untranslated 1361 1361 0 0
Lakota 100.00  100.0% untranslated 1361 1361 0 0
Ojibwe 100.00  100.0% untranslated 1361 1361 0 0
Spanish 000.00  100.0% translated 0 0 14 14 2017-09-30 08:13:24 UTC 2017-09-30 Jose Luis Tirado
Tlingit 100.00  100.0% untranslated 1361 1361 0 0
Yiddish 097.28  2.71858927259% translated  97.2814107274% untranslated 1324 1324 0 0 2012-09-21 15:14:30 UTC 2012-09-21 Raphael Finkel
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Template "gtk-3.0-properties" in Ubuntu Artful package "gtk+3.0"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 2225 2225 0 0
Dakota 100.00  100.0% untranslated 2225 2225 0 0
Hawaiian 100.00  100.0% untranslated 2225 2225 0 0
Inuktitut 100.00  100.0% untranslated 2225 2225 0 0
Lakota 100.00  100.0% untranslated 2225 2225 0 0
Ojibwe 100.00  100.0% untranslated 2225 2225 0 0
Spanish 000.00  100.0% translated 0 0 18 18 2017-08-25 16:38:18 UTC 2017-08-25 Jose Luis Tirado
Tlingit 100.00  100.0% untranslated 2225 2225 0 0
Yiddish 070.56  29.4382022472% translated  70.5617977528% untranslated 1570 1570 0 0 2012-09-21 14:37:54 UTC 2012-09-21 Raphael Finkel
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Key to this table: “Unchanged” means Translated
and “untranslated” means just that, Untranslated

Other versions of gtk+3.0 in Ubuntu