Custom Fields
Summary
Keychain introduces a new custom field type to your system named Delegate Users Field.
This custom field displays the delegates of one or more users, according to its configured delegation source, policy, and delegations defined on the Delegation Configuration page.
It is a read-only custom field. It doesn't allow you to edit values if put on edit or transition screens.
You can create a new custom field of this type using Jira Administration >> Issues >> Custom Fields >> Add custom field.
Configure Custom Field
Any custom field can be configured using the Configure menu item in the custom field's context menu on the Custom Fields page.

Once you open the configuration page of the custom field, click on the Edit Delegator link to configure the custom field.

The Configuration Page
The Keychain field's configuration screen is shown below:

Delegation Sources (Show Delegates of)
The field can be configured to get its Delegator from a number of sources.
Please note that the Current Issue name referenced below is the issue that this custom field is displaying a value for.
Assignee
If configured for Assignee, the field will take the assignee of the current issue as Delegator and will display the Delegates defined for that user as its field value.
Reporter
If configured for Reporter, the field will take the reporter of the current issue as Delegator and will display the Delegates defined for that user as its field value.
Project Lead
If configured for Project Lead, the field will take the project lead of the project (that the current issue is in) as Delegator and will display the Delegates defined for that user as its field value.
Single User
If configured for a Single User, the field will ask you to pick a user. Then it will use that user as Delegator and will display the Delegates defined for that user as its field value.
Project Role
If configured for a Project Role, the field will ask you to pick a project role. Then it will collect the users and user groups in the selected role (for the project that the current issue is in), use them as Delegators and will display the Delegates defined for those users as its field value.
User Group
If configured for a User Group, the field will ask you to pick a user group. Then it will use the selected user groups as Delegators and will display the Delegates defined for those users as its field value.
User Custom Field
If configured for a User Custom Field, the field will ask you to pick one of the Single User Picker or Multi User Picker custom fields on your system. Then it will take the users in the selected user picker of the current issue as Delegators and will display the Delegates defined for those users as its field value.
Category
Category selection determines which delegation category the delegate will be based on.
If a specific category is selected, the delegator's delegate in that category and (since the General category implicitly includes all other categories) General category will be shown in the custom field.
If General is selected, the delegator's delegates in the General category will be shown in the custom field.
Dynamic Categories
It is possible to make the category selection dynamic, based on a field value on the issue.
When you choose “<Get category from issue field>” option as the Category, supported system/custom fields will be listed in a dropdown next to the category selection, and the user will be asked to select an issue field.

Keychain will look at the value of the selected issue field for each issue and try to match it with a category name. If it finds a match, it will use that as the category.
If the selected field value is empty, or there is no matching category, the General category will be used.
If the selected field is a multi-select field, Keychain will try to match all values with categories and use the delegates for all matching categories.
General category is always included.
Field values not matching a category name will simply be ignored.
If no values match a category name, the delegate list will include only the delegates for the General category (if any).
Delegation Policy
The policy selection determines how the custom field processes Delegations and calculates the users to display in the custom field.
See the Delegation Policies page for a detailed explanation of each policy option.
(The "Include Source Users" selection, which was available in old versions of Keychain, is superseded by the delegation policy selection)