Hello, should one want to localize the submit button of any custom workflow transition screen it would be necessary to add a property string in
com/atlassian/jira/web/action/JiraWebActionSupport.properties
in the language pack and set the transition property jira.i18n.submit to that. Unfortunately this doesn't work because
boolean com.atlassian.jira.web.action.admin.workflow.AbstractViewWorkflowMetaAttributes.isReservedKey(String key)
uses
String[] com.atlassian.jira.workflow.JiraWorkflow.JIRA_META_ATTRIBUTE_ALLOWED_LIST
to refuse jira. scoped properties that are not explicitly defined.

I think jira.i18n.submit should belong to the array

Best Regards,
Edoardo