CRM Data Backup - list of field descriptions / clarification

CRM Data Backup - list of field descriptions / clarification

Hello,

is there any documentation on the fields within the backup download files? Some fields are very clear and obvious, however some less-so. eg there is a "LAST_ACTION" field that contains a number. I'm assuming the number represents the type of last action but I'm not sure what these are.

It would be useful if the fields file contained  short description, especially the less-obvious fields.

Thanks