ungoogled-chromium/patches/extra/ungoogled-chromium/add-flag-to-configure-extension-downloading.patch

# Add extension-mime-request-handling chrome://flag to tweak the behavior of
# extension MIME types

--- a/chrome/browser/download/download_crx_util.cc
+++ b/chrome/browser/download/download_crx_util.cc
@@ -8,6 +8,7 @@
 
 #include <memory>
 
+#include "base/command_line.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/crx_installer.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
@@ -128,6 +129,14 @@ scoped_refptr<extensions::CrxInstaller>
   return installer;
 }
 
+bool ShouldDownloadAsRegularFile() {
+    const base::CommandLine& command_line =
+        *base::CommandLine::ForCurrentProcess();
+    return command_line.HasSwitch("extension-mime-request-handling") &&
+        command_line.GetSwitchValueASCII("extension-mime-request-handling") ==
+        "download-as-regular-file";
+}
+
 bool IsExtensionDownload(const DownloadItem& download_item) {
   if (download_item.GetTargetDisposition() ==
       DownloadItem::TARGET_DISPOSITION_PROMPT)
@@ -136,7 +145,7 @@ bool IsExtensionDownload(const DownloadI
   if (download_item.GetMimeType() == extensions::Extension::kMimeType ||
       extensions::UserScript::IsURLUserScript(download_item.GetURL(),
                                               download_item.GetMimeType())) {
-    return true;
+    return !ShouldDownloadAsRegularFile();
   } else {
     return false;
   }
--- a/chrome/browser/download/download_crx_util.h
+++ b/chrome/browser/download/download_crx_util.h
@@ -43,6 +43,10 @@ scoped_refptr<extensions::CrxInstaller>
     Profile* profile,
     const download::DownloadItem& download_item);
 
+// Returns true if the user wants all extensions to be downloaded as regular
+// files.
+bool ShouldDownloadAsRegularFile();
+
 // Returns true if this is an extension download. This also considers user
 // scripts to be extension downloads, since we convert those automatically.
 bool IsExtensionDownload(const download::DownloadItem& download_item);
--- a/chrome/browser/download/download_target_determiner.cc
+++ b/chrome/browser/download/download_target_determiner.cc
@@ -1055,10 +1055,12 @@ DownloadConfirmationReason DownloadTarge
     return DownloadConfirmationReason::SAVE_AS;
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
-  // Don't prompt for extension downloads if the installation site is white
-  // listed.
-  if (download_crx_util::IsTrustedExtensionDownload(GetProfile(), *download_))
-    return DownloadConfirmationReason::NONE;
+  if (!download_crx_util::ShouldDownloadAsRegularFile()) {
+    // Don't prompt for extension downloads.
+    if (download_crx_util::IsTrustedExtensionDownload(GetProfile(), *download_) ||
+        filename.MatchesExtension(extensions::kExtensionFileExtension))
+      return DownloadConfirmationReason::NONE;
+  }
 #endif
 
   // Don't prompt for file types that are marked for opening automatically.
--- a/chrome/browser/extensions/extension_management.cc
+++ b/chrome/browser/extensions/extension_management.cc
@@ -10,6 +10,7 @@
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/command_line.h"
 #include "base/containers/contains.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_functions.h"
@@ -237,6 +238,13 @@ bool ExtensionManagement::IsInstallation
 bool ExtensionManagement::IsOffstoreInstallAllowed(
     const GURL& url,
     const GURL& referrer_url) const {
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch("extension-mime-request-handling") &&
+      command_line.GetSwitchValueASCII("extension-mime-request-handling") ==
+      "always-prompt-for-install") {
+    return true;
+  }
   // No allowed install sites specified, disallow by default.
   if (!global_settings_->has_restricted_install_sources)
     return false;
--- a/chrome/browser/ungoogled_flag_choices.h
+++ b/chrome/browser/ungoogled_flag_choices.h
@@ -4,4 +4,13 @@
 
 #ifndef CHROME_BROWSER_UNGOOGLED_FLAG_CHOICES_H_
 #define CHROME_BROWSER_UNGOOGLED_FLAG_CHOICES_H_
+const FeatureEntry::Choice kExtensionHandlingChoices[] = {
+    {flags_ui::kGenericExperimentChoiceDefault, "", ""},
+    {"Download as regular file",
+     "extension-mime-request-handling",
+     "download-as-regular-file"},
+    {"Always prompt for install",
+     "extension-mime-request-handling",
+     "always-prompt-for-install"},
+};
 #endif  // CHROME_BROWSER_UNGOOGLED_FLAG_CHOICES_H_
--- a/chrome/browser/ungoogled_flag_entries.h
+++ b/chrome/browser/ungoogled_flag_entries.h
@@ -12,4 +12,8 @@
      "Enable stacking in the tab strip",
      "Forces tabs to be stacked in the tab strip. Otherwise, they follow default behavior.  ungoogled-chromium flag.",
      kOsAll, SINGLE_VALUE_TYPE("enable-stacked-tab-strip")},
+    {"extension-mime-request-handling",
+     "Handling of extension MIME type requests",
+     "Used when deciding how to handle a request for a CRX or User Script MIME type.  ungoogled-chromium flag.",
+     kOsAll, MULTI_VALUE_TYPE(kExtensionHandlingChoices)},
 #endif  // CHROME_BROWSER_UNGOOGLED_FLAG_ENTRIES_H_