Query the SourceMember Object to Get Change Information

The SourceMember object stores the state of changes to metadata source components. If you're using a sandbox enabled for source tracking, you can query SourceMember to get information about component changes.

For example, the ChangedBy field on SourceMember provides the ID of the User who made the last change to a component. To display a list of changed components with information about the user who made the most recent change, use a query similar to:

1sfdx force:data:soql:query -q "SELECT MemberName, MemberType, ChangedBy, RevisionCounter FROM SourceMember" -t -u MyDevSandbox

Where MyDevSandbox is the username or alias of the sandbox you're querying. The response gives you the ID of the User who last changed each component.

1MEMBERNAME                   MEMBERTYPE    CHANGEDBY        REVISIONCOUNTER
2───────────────────────────  ────────────  ───────────────  ──
3Account.MyTextField__c       CustomField   0056g000000FDuZ  1
4Contact.MyField__c           CustomField   0056g000000FDuZ  11
5Admin                        Profile       0051k000002KW4R  54
6MyObj1__c-MyObj1 Layout      Layout        0051k000002KW4R  55
7Account-Account Layout       Layout        0056g000000FDuZ  33
8Contact-Contact Layout       Layout        0056g000000FDuZ  45
9MyObj1__c                    CustomObject  0051k000002KW4R  57
10TVRemoteControl              ApexClass     0056g000000FDuZ  53

Run another query to map IDs in the CHANGEDBY field to usernames.

1sfdx force:data:soql:query -q "SELECT Id,Username,Name FROM User" -u MyDevSandbox

And the result is similar to:

1ID                  USERNAME                                NAME
2──────────────────  ──────────────────────────────────────  ──────
30051k000002KW4RAAW  dev2@example.com.devsb1                   Dev2
40056g000000FDuZAAW  admin@example.com.devsb1                  Admin User

Salesforce DX Developer Guide

Query the SourceMember Object to Get Change Information