diff --git a/Lombiq.Tests.UI/Extensions/StringExtensions.cs b/Lombiq.Tests.UI/Extensions/StringExtensions.cs
deleted file mode 100644
index 8a8551c01..000000000
--- a/Lombiq.Tests.UI/Extensions/StringExtensions.cs
+++ /dev/null
@@ -1,67 +0,0 @@
-using System;
-using System.IO;
-using System.Linq;
-
-namespace Lombiq.Tests.UI.Extensions;
-
-public static class StringExtensions
-{
-    // The first array contains every invalid character in Windows. This is the union of GetInvalidFileNameChars() and
-    // GetInvalidPathChars() evaluated on Windows (for FAT and NTFS). Linux file systems aren't as strict, they only
-    // forbid forward slash ('/') and null character ('\0'). This is a subset of the invalid characters on Windows. So
-    // to make the paths work across all systems (e.g. when we plan to back up to an NTFS store or use GitHub's
-    // "actions/upload-artifact" action) we have to carry the banned Windows characters across operating systems.
-    // GetInvalidFileNameChars() and GetInvalidPathChars() are still included in case they contain more characters on
-    // untested operating systems.
-    private static readonly Lazy<char[]> _invalidPathCharacters = new(() => new[]
-        {
-            '\0',
-            '\u0001',
-            '\u0002',
-            '\u0003',
-            '\u0004',
-            '\u0005',
-            '\u0006',
-            '\a',
-            '\b',
-            '\t',
-            '\n',
-            '\v',
-            '\f',
-            '\r',
-            '\u000e',
-            '\u000f',
-            '\u0010',
-            '\u0011',
-            '\u0012',
-            '\u0013',
-            '\u0014',
-            '\u0015',
-            '\u0016',
-            '\u0017',
-            '\u0018',
-            '\u0019',
-            '\u001a',
-            '\u001b',
-            '\u001c',
-            '\u001d',
-            '\u001e',
-            '\u001f',
-            '|',
-            ':',
-            '"',
-            '<',
-            '>',
-            '*',
-            '?',
-        }
-        .Union(Path.GetInvalidFileNameChars())
-        .Union(Path.GetInvalidPathChars())
-        .ToArray());
-
-    public static string MakeFileSystemFriendly(this string text) =>
-        string
-            .Join("_", text.Split(_invalidPathCharacters.Value))
-            .Replace('.', '_')
-            .Replace(' ', '-');
-}
diff --git a/Lombiq.Tests.UI/Services/UITestExecutor.cs b/Lombiq.Tests.UI/Services/UITestExecutor.cs
index 0eda2f395..caa8bae97 100644
--- a/Lombiq.Tests.UI/Services/UITestExecutor.cs
+++ b/Lombiq.Tests.UI/Services/UITestExecutor.cs
@@ -1,5 +1,4 @@
 using Lombiq.HelpfulLibraries.Common.Utilities;
-using Lombiq.Tests.UI.Extensions;
 using Lombiq.Tests.UI.Helpers;
 using Lombiq.Tests.UI.Models;
 using Lombiq.Tests.UI.Services.GitHub;