Please add some documentation for the 'Migrate users from one directory to another' Functionality

This new feature was added to the User Directories, as in the attached screenshot. Unfortunately we don't seem to have any documentation on it and it's a bit confusing about what the functionality does and does not do.

So far, based from the case I worked on and JRA-24213 it seems to be able to:

• Migrate all users from JIRA Internal to Delegated LDAP.
• Migrate all users from Delegated LDAP to JIRA Internal.
• Migrate all users from Delegated LDAP to Delegated LDAP.

It does not support (requested in JRA-27868):

• Migrating a specific set of users from one directory to another.
• "Connector" User Directories - so direct to the LDAP Server (e.g.: Active Directory).
• Migrating groups only.

It seems to have the following features:

• If you, the currently logged in user, are in the directory to be migrated from, your user data will not be migrated.
• Users and groups will not be migrated if they already exist in the target directory. For example, if dcurrie exists in JIRA Internal and JIRA Delegated LDAP, yet has different groups in JIRA Internal, when migrating from one to the other, that user will be skipped an the groups will not be migrated.

And of note:

• Project Roles are not affected as they do not seem to be user directory specific (unlike groups).

This originally derived from JRA-24213 and now has a subsequent issue to add more functionality to the feature, JRA-27868.

Can you please add some documentation for this feature? (it came in as part of 5.0.3 and somehow missed the release notes).

Thank you!