I pushed a change draft for Issue #234 : “Consider making originalUriBaseIds a dictionary of file location objects”: Documents/ChangeDrafts/Active/sarif-v2.0-issue-234-originalUriBaseIds-are-fileLocations.docx The idea is to be able to specify a hierarchy of URI base ids under a common root. With the current design, you have to say this: { "originalUriBaseIds": { "SOURCE_ROOT": "file:///C:/repos/MyProject/src/", "TEST_SOURCE_ROOT": "file:///C:/repos/MyProject/src/tests/", "BIN_ROOT": "file:///C:/repos/MyProject/bin" }, ... } With the proposed design, you can say this: { "originalUriBaseIds": { "PROJECT_ROOT": { "uri": "file:///C:/repos/MyProject/" }, "SOURCE_ROOT": { "uri": "src/" "uriBaseId": "PROJECT_ROOT" }, "TEST_SOURCE_ROOT": { "uri": " tests/", "uriBaseId": "SOURCE_ROOT" }, "BIN_ROOT": { "uri": "bin/", "uriBaseId": "PROJECT_ROOT" } }, ... } Now only one of the original uriBaseIds is non-deterministic, and a consumer that “rebases” URIs from one machine to another need only prompt the user for one location. We will move its adoption at TC #24 on Wednesday, September 26 th . Thanks, Larry