Hi vijay,
Unfortunately, there's not really any formal documentation that describes each settings key, since people are typically looking for info in the opposite direction (ie. trying to find the setting key for a particular setting they found in the UI). I know it's not ideal, but because most settings do have a UI element (ie. Admin Setting), you can often use the Text Editor in studio to get more information about a paritcular settings key. For example, if you search for "video.require_moderation" in the Text Editor, you'll get the following results:
video.require_moderation.title = Require moderator approval of videos video.require_moderation.description =
If the text keys don't give you enough information about the particular setting, now that you know the title of the setting ("Require moderation appproval of videos"), you could look in the Admin documentation to find more about how that setting is used. And if a setting proves to be particularly elusive (ie. no text keys or no additional info in admin guide), feel free to ask here and we can try to help. There are some settings that have been deprecated over time, but remain in the back-end to avoid causing issuses with communities that may still be using those settings.
