slightly expand the answer to 'Is go.sum a lock file?'
diff --git a/Modules.md b/Modules.md
index a7b3d74..c1ce915 100644
--- a/Modules.md
+++ b/Modules.md
@@ -616,7 +616,9 @@
### Is 'go.sum' a lock file? Why does 'go.sum' include information for module versions I am no longer using?
-No, `go.sum` is not a lock file. For validation purposes, `go.sum` contains the expected cryptographic checksums of the content of specific module versions. See the [FAQ below](https://github.com/golang/go/wiki/Modules#should-i-commit-my-gosum-file-as-well-as-my-gomod-file) for more details on `go.sum` (including why you typically should check in `go.sum`) as well as the ["Module downloading and verification"](https://tip.golang.org/cmd/go/#hdr-Module_downloading_and_verification) section in the tip documentation.
+No, `go.sum` is not a lock file. The `go.mod` files in a build provide enough information for 100% reproducible builds.
+
+For validation purposes, `go.sum` contains the expected cryptographic checksums of the content of specific module versions. See the [FAQ below](https://github.com/golang/go/wiki/Modules#should-i-commit-my-gosum-file-as-well-as-my-gomod-file) for more details on `go.sum` (including why you typically should check in `go.sum`) as well as the ["Module downloading and verification"](https://tip.golang.org/cmd/go/#hdr-Module_downloading_and_verification) section in the tip documentation.
In part because `go.sum` is not a lock file, it retains cryptographic checksums for module versions even after you stop using a module or particular module version. This allows validation of the checksums if you later resume using something, which provides additional safety.
