I've investigated this further. Here are my findings:
1. If you switch to German on the license screen (setuplicense), then that screen and the ones related to setting up the database (setupdb-start, setupstandarddb-start, setupdatasourcedb-start) will be entirely in German.
2. The screens related to setting up data (setupdata-start, setup-restore-start) and user management (setupusermanagementchoice-start, setupadministrator-start, connecttojira-start) will be entirely in English.
3. The success screen (finishsetup) will have German chrome (header, footer) but English content.
A few good leads:
1. Confluence switches Spring context, from setup to main, between the database-setup and data-setup steps. This is a prime candidate for an underlying cause for this bug.
2. com.atlassian.config.bootstrap.DefaultAtlassianBootstrapManager#isSetupComplete starts returning true at finishsetup. Also, see com.atlassian.confluence.web.filter.LanguageExtractionFilter#getLocaleManager. Conspicuous.
Hi All
Given that this issue has been around now for a year and that it's only a minor issue with very few votes I'm going to close this one out as won't fix as I feel it better reflect the true status of this issue. Should this be raised again in the future we'll reconsider this.
Regards
Steve Haffenden
Confluence Bugmaster
Atlassian