diff --git a/__snapshots__/github.js b/__snapshots__/github.js
index 4b6d9d883..c43b3ff46 100644
--- a/__snapshots__/github.js
+++ b/__snapshots__/github.js
@@ -2,6 +2,24 @@ exports['GitHub commentOnIssue can create a comment 1'] = {
   "body": "This is a comment"
 }
 
+exports['GitHub commitsSince backfills commit files without pull requests 1'] = [
+  {
+    "sha": "e6daec403626c9987c7af0d97b34f324cd84320a",
+    "message": "Merge pull request #7 from chingor13/feature-branch-plain-merge\n\nfeat: feature that will be plain merged",
+    "files": [],
+    "pullRequest": {
+      "sha": "e6daec403626c9987c7af0d97b34f324cd84320a",
+      "number": 7,
+      "baseBranchName": "main",
+      "headBranchName": "feature-branch-plain-merge",
+      "title": "feat: feature that will be plain merged",
+      "body": "",
+      "labels": [],
+      "files": []
+    }
+  }
+]
+
 exports['GitHub commitsSince finds commits up until a condition 1'] = [
   {
     "sha": "e6daec403626c9987c7af0d97b34f324cd84320a",
diff --git a/src/github.ts b/src/github.ts
index e27862fd4..a310a053c 100644
--- a/src/github.ts
+++ b/src/github.ts
@@ -365,44 +365,64 @@ export class GitHub {
     }
     const history = response.repository.ref.target.history;
     const commits = (history.nodes || []) as GraphQLCommit[];
+    const commitData: Commit[] = [];
+    for (const graphCommit of commits) {
+      const commit: Commit = {
+        sha: graphCommit.sha,
+        message: graphCommit.message,
+        files: [],
+      };
+      const pullRequest = graphCommit.associatedPullRequests.nodes.find(pr => {
+        return pr.mergeCommit && pr.mergeCommit.oid === graphCommit.sha;
+      });
+      if (pullRequest) {
+        const files = pullRequest.files.nodes.map(node => node.path);
+        commit.pullRequest = {
+          sha: commit.sha,
+          number: pullRequest.number,
+          baseBranchName: pullRequest.baseRefName,
+          headBranchName: pullRequest.headRefName,
+          title: pullRequest.title,
+          body: pullRequest.body,
+          labels: pullRequest.labels.nodes.map(node => node.name),
+          files,
+        };
+        // We cannot directly fetch files on commits via graphql, only provide file
+        // information for commits with associated pull requests
+        commit.files = files;
+      } else {
+        // In this case, there is no squashed merge commit. This could be a simple
+        // merge commit, a rebase merge commit, or a direct commit to the branch.
+        // Fallback to fetching the list of commits from the REST API. In the future
+        // we can perhaps lazy load these.
+        commit.files = await this.getCommitFiles(graphCommit.sha);
+      }
+      commitData.push(commit);
+    }
     return {
       pageInfo: history.pageInfo,
-      data: commits.map(graphCommit => {
-        const commit: Commit = {
-          sha: graphCommit.sha,
-          message: graphCommit.message,
-          files: [],
-        };
-        const pullRequest = graphCommit.associatedPullRequests.nodes.find(
-          pr => {
-            return pr.mergeCommit && pr.mergeCommit.oid === graphCommit.sha;
-          }
-        );
-        if (pullRequest) {
-          const files = pullRequest.files.nodes.map(node => node.path);
-          commit.pullRequest = {
-            sha: commit.sha,
-            number: pullRequest.number,
-            baseBranchName: pullRequest.baseRefName,
-            headBranchName: pullRequest.headRefName,
-            title: pullRequest.title,
-            body: pullRequest.body,
-            labels: pullRequest.labels.nodes.map(node => node.name),
-            files,
-          };
-          // We cannot directly fetch files on commits via graphql, only provide file
-          // information for commits with associated pull requests
-          commit.files = files;
-        } else {
-          logger.warn(
-            `No merged pull request for commit: ${graphCommit.sha} - files unavailable`
-          );
-        }
-        return commit;
-      }),
+      data: commitData,
     };
   }
 
+  /**
+   * Get the list of file paths modified in a given commit.
+   *
+   * @param {string} sha The commit SHA
+   * @returns {string[]} File paths
+   * @throws {GitHubAPIError} on an API error
+   */
+  getCommitFiles = wrapAsync(async (sha: string): Promise<string[]> => {
+    logger.debug(`Backfilling file list for commit: ${sha}`);
+    const resp = await this.octokit.repos.getCommit({
+      owner: this.repository.owner,
+      repo: this.repository.repo,
+      ref: sha,
+    });
+    const files = resp.data.files || [];
+    return files.map(file => file.filename!).filter(filename => !!filename);
+  });
+
   private graphqlRequest = wrapAsync(
     async (
       opts: {
diff --git a/src/manifest.ts b/src/manifest.ts
index d4258d062..eb7f90a57 100644
--- a/src/manifest.ts
+++ b/src/manifest.ts
@@ -768,7 +768,6 @@ export class Manifest {
           );
         }
         this._pathsByComponent[component] = path;
-        logger.info(this._pathsByComponent);
       }
     }
     return this._pathsByComponent;
diff --git a/test/github.ts b/test/github.ts
index 4407eae47..4a3007fc9 100644
--- a/test/github.ts
+++ b/test/github.ts
@@ -14,12 +14,13 @@
 
 import * as nock from 'nock';
 import {expect} from 'chai';
-import {beforeEach, describe, it} from 'mocha';
+import {afterEach, beforeEach, describe, it} from 'mocha';
 nock.disableNetConnect();
 
 import {readFileSync} from 'fs';
 import {resolve} from 'path';
 import * as snapshot from 'snap-shot-it';
+import * as sinon from 'sinon';
 
 import {GitHub, GitHubRelease} from '../src/github';
 import {PullRequest} from '../src/pull-request';
@@ -30,6 +31,7 @@ import {DuplicateReleaseError, GitHubAPIError} from '../src/errors';
 import {fail} from 'assert';
 
 const fixturesPath = './test/fixtures';
+const sandbox = sinon.createSandbox();
 
 describe('GitHub', () => {
   let github: GitHub;
@@ -56,6 +58,9 @@ describe('GitHub', () => {
     // This shared nock will take care of some common requests.
     req = getNock();
   });
+  afterEach(() => {
+    sandbox.restore();
+  });
 
   describe('create', () => {
     it('allows configuring the default branch explicitly', async () => {
@@ -287,6 +292,7 @@ describe('GitHub', () => {
 
   describe('commitsSince', () => {
     it('finds commits up until a condition', async () => {
+      sandbox.stub(github, 'getCommitFiles').resolves([]);
       const graphql = JSON.parse(
         readFileSync(resolve(fixturesPath, 'commits-since.json'), 'utf8')
       );
@@ -307,6 +313,7 @@ describe('GitHub', () => {
     });
 
     it('paginates through commits', async () => {
+      sandbox.stub(github, 'getCommitFiles').resolves([]);
       const graphql1 = JSON.parse(
         readFileSync(resolve(fixturesPath, 'commits-since-page-1.json'), 'utf8')
       );
@@ -336,6 +343,7 @@ describe('GitHub', () => {
     });
 
     it('finds first commit of a multi-commit merge pull request', async () => {
+      sandbox.stub(github, 'getCommitFiles').resolves([]);
       const graphql = JSON.parse(
         readFileSync(resolve(fixturesPath, 'commits-since.json'), 'utf8')
       );
@@ -356,6 +364,7 @@ describe('GitHub', () => {
     });
 
     it('limits pagination', async () => {
+      sandbox.stub(github, 'getCommitFiles').resolves([]);
       const graphql1 = JSON.parse(
         readFileSync(resolve(fixturesPath, 'commits-since-page-1.json'), 'utf8')
       );
@@ -377,6 +386,7 @@ describe('GitHub', () => {
     });
 
     it('returns empty commits if branch does not exist', async () => {
+      sandbox.stub(github, 'getCommitFiles').resolves([]);
       const graphql = JSON.parse(
         readFileSync(
           resolve(fixturesPath, 'commits-since-missing-branch.json'),
@@ -396,6 +406,51 @@ describe('GitHub', () => {
       expect(commitsSinceSha.length).to.eql(0);
       req.done();
     });
+
+    it('backfills commit files without pull requests', async () => {
+      const graphql = JSON.parse(
+        readFileSync(resolve(fixturesPath, 'commits-since.json'), 'utf8')
+      );
+      req
+        .post('/graphql')
+        .reply(200, {
+          data: graphql,
+        })
+        .get(
+          '/repos/fake/fake/commits/0cda26c2e7776748072ba5a24302474947b3ebbd'
+        )
+        .reply(200, {files: [{filename: 'abc'}]})
+        .get(
+          '/repos/fake/fake/commits/c6d9dfb03aa2dbe1abc329592af60713fe28586d'
+        )
+        .reply(200, {files: [{filename: 'def'}]})
+        .get(
+          '/repos/fake/fake/commits/c8f1498c92c323bfa8f5ffe84e0ade1c37e4ea6e'
+        )
+        .reply(200, {files: [{filename: 'ghi'}]});
+      const targetBranch = 'main';
+      const commitsSinceSha = await github.commitsSince(
+        targetBranch,
+        commit => {
+          // this commit is the 2nd most recent
+          return commit.sha === 'b29149f890e6f76ee31ed128585744d4c598924c';
+        }
+      );
+      expect(commitsSinceSha.length).to.eql(1);
+      snapshot(commitsSinceSha);
+      req.done();
+    });
+  });
+
+  describe('getCommitFiles', () => {
+    it('fetches the list of files', async () => {
+      req
+        .get('/repos/fake/fake/commits/abc123')
+        .reply(200, {files: [{filename: 'abc'}]});
+      const files = await github.getCommitFiles('abc123');
+      expect(files).to.eql(['abc']);
+      req.done();
+    });
   });
 
   describe('releaseIterator', () => {