In the 'All Database Roles' section, missing the word 'all' between 'apply to' and 'but':
"The admin database provides the following roles that apply to all but the local and config databases in a mongod instance and are roughly equivalent to their single-database equivalents:"

It would read better as:
"The admin database provides the following roles that apply all databases except the local and config databases in a mongod instance and are roughly equivalent to their single-database equivalents:"