@@ -588,8 +588,19 @@ async function applyPatchToDir({ dir, patchText, reverse = false, onLog = () =>
 		return { ok: false, error, applied: [], skipped };
 	}
 	const written = await applyPatch(dir, applyText, { reverse, platform, prefix });
-	// translators: %s: the exit code of the command git apply.
-	let writeError = written.ok ? null : written.stderr.split(/\r?\n/).filter((line) => line.trim()).pop() || sprintf(__('git apply exited %s'), written.status);
+	// Why the write failed, as one whole sentence: Git's own last line when it
+	// printed one, the app's own words otherwise.
+	let message = null;
+	if (!written.ok) {
+		const stderr = written.stderr.split(/\r?\n/).filter((line) => line.trim()).pop();
+		if (stderr) {
+			// translators: %s: why writing the patch failed, Git's own message, in English.
+			message = sprintf(__('writing %s'), stderr);
+		} else {
+			// translators: %s: the exit code of the command git apply.
+			message = sprintf(__('writing git apply exited %s'), written.status);
+		}
+	}
 	// Windows Git can exit 0 without creating a file beneath a regular-file
 	// parent (#413). Check the actual destinations before claiming success.
 	// Git still decides the contents; this only detects an omitted write.
@@ -601,15 +612,13 @@ async function applyPatchToDir({ dir, patchText, reverse = false, onLog = () =>
 				await fs.promises.lstat(path.join(dir, relPath));
 			} catch (e) {
 				// translators: 1: the path of a file the patch writes. 2: why it could not be read back, as the system said it.
-				writeError = sprintf(__('could not verify %1$s after git apply: %2$s'), relPath, e.message);
+				message = sprintf(__('writing could not verify %1$s after git apply: %2$s'), relPath, e.message);
 				break;
 			}
 		}
 	}
-	if (writeError) {
+	if (message) {
 		const recovery = rollback(dir, snapshot);
-		// translators: %s: why writing the patch failed, often Git's own message in English.
-		const message = sprintf(__('writing %s'), writeError);
 		if (recovery.length) {
 			// translators: %s: the files that could not be put back, and why, separated by semicolons.
 			onLog(`\n${sprintf(__('The patch could not be written, and the checkout could not be fully put back — it is in an unknown state. Could not undo: %s'), recovery.join('; '))}\n`);
 
@@ -503,7 +503,7 @@ function planApply({ files, dirtyPaths = [] } = {}) {
 		// applied from a text diff; one that carries its bytes is applied like
 		// any other file (#385). Naming the first kind is the difference
 		// between "this patch is partly unapplied" and a silent gap.
-		unsupported: list.filter((f) => f.kind === 'binary' && !f.hasBinaryData).map((f) => f.path || '(unnamed binary file)'),
+		unsupported: list.filter((f) => f.kind === 'binary' && !f.hasBinaryData).map((f) => f.path || __('(unnamed binary file)')),
 		// Same rule the trunk update uses (#94): the lockfile moving is what
 		// makes an install necessary rather than merely possible.
 		needsInstall: touched.has('package-lock.json')
 
@@ -7,7 +7,8 @@
 // as it is: what a pull request's preview and banner say (pr-checkout.cjs,
 // watch-activity.cjs), what an applied patch says (applied-layer.cjs), why a
 // patch did not fit (apply-conflict.cjs) and the steps of an apply
-// (update-plan.cjs). Each is translated where it is written, not here.
+// (update-plan.cjs). Each is translated where it is written, not here; the
+// banner's and the steps' words are still English until their own batches.
 'use strict';
 
 const { __, _n, sprintf } = require('@wordpress/i18n');
 
@@ -96,8 +96,7 @@ function describePrPreview({ number, files = [], needsInstall = false, exists =
 		headline,
 		actionLabel: exists && moved && hasEdits ? __('Return to saved copy') : __('Apply and rebuild'),
 		closedNote: state === 'closed' ? __('This pull request is closed. You can still check out its last head to investigate it.') : '',
-		// translators: %s: the name of a file, package-lock.json.
-		installNote: needsInstall ? sprintf(__('It changes %s, so dependencies will be installed before the rebuild.'), 'package-lock.json') : ''
+		installNote: needsInstall ? __('It changes package-lock.json, so dependencies will be installed before the rebuild.') : ''
 	};
 }
 
 
@@ -176,7 +176,7 @@ async function fetchAttachment(url) {
 	// not the caller's string: the request rides the session cookie, so the URL
 	// fetched has to be the one that passed the check.
 	const safe = secureTracUrl(url);
-	if (!safe) return { ok: false, error: 'Only https core.trac.wordpress.org attachments are allowed' };
+	if (!safe) return { ok: false, error: __('Only https core.trac.wordpress.org attachments are allowed') };
 
 	let res;
 	try {
 
@@ -125,7 +125,7 @@ test('a checkout\'s sentences are said in the locale: one per kind of work item,
 
 	const preview = describePrPreview({ number: 7, files: [{ path: 'a.php' }, { path: 'b.php' }], needsInstall: true, state: 'closed' });
 	assert.equal(preview.headline, pseudo('PR #%1$d changes %2$d files.', 7, 2));
-	assert.equal(preview.installNote, pseudo('It changes %s, so dependencies will be installed before the rebuild.', 'package-lock.json'));
+	assert.equal(preview.installNote, pseudoLocalize('It changes package-lock.json, so dependencies will be installed before the rebuild.'));
 	assert.equal(describePrPreview({ number: 7, files: [{ path: 'a.php' }] }).headline, pseudo('PR #%1$d changes %2$d file.', 7, 1));
 	assert.equal(describePrPreview({ number: 7, exists: true, moved: true, hasEdits: true }).actionLabel, pseudoLocalize('Return to saved copy'));
 });
Original file line number	Diff line number	Diff line change
`@@ -96,8 +96,7 @@ function describePrPreview({ number, files = [], needsInstall = false, exists =`
`96`	`96`	`headline,`
`97`	`97`	`actionLabel: exists && moved && hasEdits ? __('Return to saved copy') : __('Apply and rebuild'),`
`98`	`98`	`closedNote: state === 'closed' ? __('This pull request is closed. You can still check out its last head to investigate it.') : '',`
`99`		`- // translators: %s: the name of a file, package-lock.json.`
`100`		`- installNote: needsInstall ? sprintf(__('It changes %s, so dependencies will be installed before the rebuild.'), 'package-lock.json') : ''`
	`99`	`+ installNote: needsInstall ? __('It changes package-lock.json, so dependencies will be installed before the rebuild.') : ''`
`101`	`100`	`};`
`102`	`101`	`}`
`103`	`102`