How to get database role securables

Question: I  need to extract the securables for a user created SQL Server database role. For example , the Explicit Permissions  including the Permission,Grantor,Grant,With Grant and Deny.  And also the Securables - Schema,Name,Type

How can I get this information via t-sql?

Answer: Initially you can check the SQL Server Profiler and trap the actual sql query executed as part of generating the display. An example of the query is :

declare @name varchar(20)
set @name = 'myuser'
SELECT
ascii(prmssn.state) AS [PermissionState],
null AS [Code],
grantor_principal.name AS [Grantor],
prmssn.type AS [SqlCodePP],
CASE WHEN (prmssn.class=4 or prmssn.class=101 ) THEN CASE (SELECT oc.type FROM sys.server_principals AS oc WHERE oc.principal_id = prmssn.major_id) WHEN 'R' THEN CASE prmssn.class WHEN 4 THEN 201 ELSE 301 END WHEN 'A' THEN 202 ELSE CASE prmssn.class WHEN 4 THEN 200 ELSE 101 END END ELSE prmssn.class END AS [HiddenObjectClass]
FROM
sys.server_permissions AS prmssn
INNER JOIN sys.server_principals AS grantor_principal ON grantor_principal.principal_id = prmssn.grantor_principal_id
INNER JOIN sys.server_principals AS grantee_principal ON grantee_principal.principal_id = prmssn.grantee_principal_id
WHERE
(prmssn.class = 100)and(grantee_principal.name=@name)

I have modified this statement slightly . One thing you'll notice with the output is some esoteric columns - which you may not have previously explored e.g sys.server_permissions.PermissionState &  sys.server_permissions.class

sys.server_permissions.class = Identifies class of thing on which permission exists

sys.server_permissions.State = Permission state

sys.server_permissions.Type = server permission type

Just using the query above you'll get some data , but unless you're familiar with the codes and the permissions state numbers , it can be of little use. 

A more readable query and  more useful to read Is:

SELECT
       grantee_principal_id,
       class_desc,
       [permission_name],
       state_desc
FROM sys.server_permissions
WHERE grantee_principal_id IN(281);

Some more reading on user permissions

How to Script database role permissions and securables

SQL Server database roles and GDPR

Powershell sql server security audit