Dictionary/map that contains information about the current running version of ansible, it has the following keys: full, major, minor, revision and string.
group_names
List of groups the current host is part of
groups
A dictionary/map with all the groups in inventory and each group has the list of hosts that belong to it
hostvars
A dictionary/map with all the hosts in inventory and variables assigned to them
inventory_hostname
The inventory name for the 'current' host being iterated over in the play
inventory_hostname_short
The short version of `inventory_hostname`
inventory_dir
The directory of the inventory source in which the `inventory_hostname` was first defined
inventory_file
The file name of the inventory source in which the `inventory_hostname` was first defined
Connection variables are normally used to set the specifics on how to execute actions on a target. Most of them correspond to connection plugins, but not all are specific to them; other plugins like shell, terminal and become are normally involved.
Only the common ones are described as each connection/become/shell/etc plugin can define its own overrides and specific variables.