diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
index 4c296d20fa..352740a591 100644
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -20,6 +20,7 @@
 #include "progress.h"
 #include "video/video_driver.hpp"
 #include "strings_func.h"
+#include "textfile_gui.h"
 
 #include "fileio_func.h"
 #include "fios.h"
@@ -878,29 +879,5 @@ bool GRFConfig::IsOpenTTDBaseGRF() const
  */
 const char *GRFConfig::GetTextfile(TextfileType type) const
 {
-	static const char * const prefixes[] = {
-		"readme",
-		"changelog",
-		"license",
-	};
-	assert_compile(lengthof(prefixes) == TFT_END);
-
-	const char *prefix = prefixes[type];
-
-	if (this->filename == NULL) return NULL;
-
-	static char file_path[MAX_PATH];
-	strecpy(file_path, this->filename, lastof(file_path));
-
-	char *slash = strrchr(file_path, PATHSEPCHAR);
-	if (slash == NULL) return NULL;
-
-	seprintf(slash + 1, lastof(file_path), "%s_%s.txt", prefix, GetCurrentLanguageIsoCode());
-	if (FioCheckFileExists(file_path, NEWGRF_DIR)) return file_path;
-
-	seprintf(slash + 1, lastof(file_path), "%s_%.2s.txt", prefix, GetCurrentLanguageIsoCode());
-	if (FioCheckFileExists(file_path, NEWGRF_DIR)) return file_path;
-
-	seprintf(slash + 1, lastof(file_path), "%s.txt", prefix);
-	return FioCheckFileExists(file_path, NEWGRF_DIR) ? file_path : NULL;
+	return ::GetTextfile(type, NEWGRF_DIR, this->filename);
 }
diff --git a/src/textfile_gui.cpp b/src/textfile_gui.cpp
index 93138eac37..3a4954323a 100644
--- a/src/textfile_gui.cpp
+++ b/src/textfile_gui.cpp
@@ -192,3 +192,39 @@ TextfileWindow::TextfileWindow(TextfileType file_type) : Window(), file_type(fil
 	this->hscroll->SetCount(this->max_length + WD_FRAMETEXT_LEFT + WD_FRAMETEXT_RIGHT);
 	this->hscroll->SetStepSize(10); // Speed up horizontal scrollbar
 }
+
+/**
+ * Search a textfile file next to the given content.
+ * @param type The type of the textfile to search for.
+ * @param dir The subdirectory to search in.
+ * @param filename The filename of the content to look for.
+ * @return The path to the textfile, \c NULL otherwise.
+ */
+const char *GetTextfile(TextfileType type, Subdirectory dir, const char *filename)
+{
+	static const char * const prefixes[] = {
+		"readme",
+		"changelog",
+		"license",
+	};
+	assert_compile(lengthof(prefixes) == TFT_END);
+
+	const char *prefix = prefixes[type];
+
+	if (filename == NULL) return NULL;
+
+	static char file_path[MAX_PATH];
+	strecpy(file_path, filename, lastof(file_path));
+
+	char *slash = strrchr(file_path, PATHSEPCHAR);
+	if (slash == NULL) return NULL;
+
+	seprintf(slash + 1, lastof(file_path), "%s_%s.txt", prefix, GetCurrentLanguageIsoCode());
+	if (FioCheckFileExists(file_path, dir)) return file_path;
+
+	seprintf(slash + 1, lastof(file_path), "%s_%.2s.txt", prefix, GetCurrentLanguageIsoCode());
+	if (FioCheckFileExists(file_path, dir)) return file_path;
+
+	seprintf(slash + 1, lastof(file_path), "%s.txt", prefix);
+	return FioCheckFileExists(file_path, dir) ? file_path : NULL;
+}
diff --git a/src/textfile_gui.h b/src/textfile_gui.h
index 56760505ce..846e93c563 100644
--- a/src/textfile_gui.h
+++ b/src/textfile_gui.h
@@ -16,6 +16,8 @@
 #include "textfile_type.h"
 #include "window_gui.h"
 
+const char *GetTextfile(TextfileType type, Subdirectory dir, const char *filename);
+
 /** Window for displaying a textfile */
 struct TextfileWindow : public Window, MissingGlyphSearcher {
 	TextfileType file_type;              ///< Type of textfile to view.