A few translation issues

When I was translating Gallery 3 I found a few problems:
1. I tried to fix wrong translation, but I wasn’t able to do it, because translation part of page (bottom) doesn’t show all the plurals we have in Czech language and „Save translation“ button is also missing.
2. On language page is name of Czech language shown „Česky“ instead of „česky“.
3. On User and Groups page is not possible to translate names of groups „Everybody“ and „Registered users“ and also users „admin“ and „guest“
4. And can somebody explain me, please, what „Manage Identity Providers“ page does?

Thank you.