diff --git a/admin_manual/installation/nginx-root.conf.sample b/admin_manual/installation/nginx-root.conf.sample
index 5e571361d6d..ef701f6230b 100644
--- a/admin_manual/installation/nginx-root.conf.sample
+++ b/admin_manual/installation/nginx-root.conf.sample
@@ -1,6 +1,9 @@
-# Version 2025-07-23
+# Nextcloud nginx configuration — root installation
+# Version 2026-03-26
 
+# PHP-FPM backend.
 upstream php-handler {
+    # Use one of the options below, not both:
     server 127.0.0.1:9000;
     #server unix:/run/php/php8.2-fpm.sock;
 }
@@ -148,37 +151,69 @@ server {
     location ~ ^/(?:build|tests|config|lib|3rdparty|templates|data)(?:$|/)  { return 404; }
     location ~ ^/(?:\.|autotest|occ|issue|indie|db_|console)                { return 404; }
 
-    # Ensure this block, which passes PHP files to the PHP process, is above the blocks
-    # which handle static assets (as seen below). If this block is not declared first,
-    # then Nginx will encounter an infinite rewriting loop when it prepends `/index.php`
-    # to the URI, resulting in a HTTP 500 error response.
+    # Pass PHP requests to PHP-FPM.
+    #
+    # Important: this block must appear above the static asset locations
+    # below. Those locations fall back to `/index.php$request_uri`; if
+    # they appear first, nginx can repeatedly rewrite to `/index.php`,
+    # causing an internal redirection loop.
     location ~ \.php(?:$|/) {
-        # Required for legacy support
-        rewrite ^/(?!index|remote|public|cron|core\/ajax\/update|status|ocs\/v[12]|updater\/.+|ocs-provider\/.+|.+\/richdocumentscode(_arm64)?\/proxy) /index.php$request_uri;
-
+        # Rewrite most PHP requests to Nextcloud's front controller (`/index.php`).
+        #
+        # (Mirrors the rewrite exceptions in Nextcloud's Apache .htaccess.)
+        #
+        # Exceptions (not rewritten; must remain directly reachable):
+        #   index.php, remote.php, public.php, cron.php, status.php
+        #   ocs/v1.php, ocs/v2.php, ocs-provider/*
+        #   core/ajax/update.php, updater/*
+        #   */richdocumentscode(_arm64)?/proxy
+        #
+        # Other exceptions (e.g. /.well-known) are handled by dedicated
+        # location blocks elsewhere in this config.
+        #
+        # Caution: small edits to this regex can break routing or introduce
+        # rewrite loops.
+        rewrite ^/(?!index|remote|public|cron|status|ocs\/v[12]|ocs-provider\/.+|core\/ajax\/update|updater\/.+|.+\/richdocumentscode(_arm64)?\/proxy) /index.php$request_uri;
+
+        # Split `/file.php/path/info` into:
+        # - $fastcgi_script_name: `/file.php`
+        # - $fastcgi_path_info:   `/path/info`
+        #
+        # This is required for entry-points such as `remote.php` and `public.php`,
+        # which route requests based on PATH_INFO.
         fastcgi_split_path_info ^(.+?\.php)(/.*)$;
-        set $path_info $fastcgi_path_info;
+        set $path_info $fastcgi_path_info;    # Save before try_files resets it
 
+        # Return 404 for nonexistent PHP scripts (avoids passing arbitrary
+        # paths to PHP-FPM, which is a known security risk).
         try_files $fastcgi_script_name =404;
 
         include fastcgi_params;
-        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
-        fastcgi_param PATH_INFO $path_info;
-        fastcgi_param HTTPS on;
-
-        fastcgi_param modHeadersAvailable true;         # Avoid sending the security headers twice
-        fastcgi_param front_controller_active true;     # Enable pretty urls
         fastcgi_pass php-handler;
 
+        fastcgi_param SCRIPT_FILENAME            $document_root$fastcgi_script_name;
+        fastcgi_param PATH_INFO                  $path_info;
+        fastcgi_param HTTPS                      on;       # Assumes TLS terminates here
+        fastcgi_param modHeadersAvailable        true;     # Avoid duplicate security headers
+        fastcgi_param front_controller_active    true;     # Enable pretty URLs
+
+        # Let nginx handle HTTP error responses from PHP-FPM (e.g. custom
+        # error pages). Disable for debugging if PHP errors are being hidden.
         fastcgi_intercept_errors on;
-        fastcgi_request_buffering on;                   # Required as PHP-FPM does not support chunked transfer encoding and requires a valid ContentLength header.
 
-        # PHP-FPM 504 response timeouts
-        # Uncomment and increase these if facing timeout errors during large file uploads
+        # Required for uploads: PHP-FPM does not support chunked
+        # transfer encoding and needs a Content-Length header.
+        fastcgi_request_buffering on;
+
+        # Optional PHP-FPM timeout tuning (e.g. for 504 response timeouts).
+        # Increase these only if uploads or long-running PHP requests are
+        # timing out in your environment.
         #fastcgi_read_timeout 60s;
         #fastcgi_send_timeout 60s;
         #fastcgi_connect_timeout 60s;
 
+        # Disable on-disk buffering of FastCGI responses (reduces disk I/O at
+        # the cost of holding responses in memory).
         fastcgi_max_temp_file_size 0;
     }
 
diff --git a/admin_manual/installation/nginx-subdir.conf.sample b/admin_manual/installation/nginx-subdir.conf.sample
index 6fe1dfd7995..bf8e727d422 100644
--- a/admin_manual/installation/nginx-subdir.conf.sample
+++ b/admin_manual/installation/nginx-subdir.conf.sample
@@ -1,6 +1,9 @@
-# Version 2025-07-23
+# Nextcloud nginx configuration — subdirectory installation (/nextcloud)
+# Version 2026-03-26
 
+# PHP-FPM backend.
 upstream php-handler {
+    # Use one of the options below, not both:
     server 127.0.0.1:9000;
     #server unix:/run/php/php8.2-fpm.sock;
 }
@@ -52,7 +55,7 @@ server {
     include mime.types;
     types {
         text/javascript mjs;
-	application/wasm wasm;
+        application/wasm wasm;
     }
 
     location = /robots.txt {
@@ -147,37 +150,70 @@ server {
         location ~ ^/nextcloud/(?:build|tests|config|lib|3rdparty|templates|data)(?:$|/)    { return 404; }
         location ~ ^/nextcloud/(?:\.|autotest|occ|issue|indie|db_|console)                  { return 404; }
 
-        # Ensure this block, which passes PHP files to the PHP process, is above the blocks
-        # which handle static assets (as seen below). If this block is not declared first,
-        # then Nginx will encounter an infinite rewriting loop when it prepends
-        # `/nextcloud/index.php` to the URI, resulting in a HTTP 500 error response.
+        # Pass PHP requests to PHP-FPM.
+        #
+        # Important: this block must appear above the static asset locations
+        # below. Those locations fall back to `/nextcloud/index.php$request_uri`;
+        # if they appear first, nginx can repeatedly rewrite to
+        # `/nextcloud/index.php`, causing an internal redirection loop.
         location ~ \.php(?:$|/) {
-            # Required for legacy support
-            rewrite ^/nextcloud/(?!index|remote|public|cron|core\/ajax\/update|status|ocs\/v[12]|updater\/.+|ocs-provider\/.+|.+\/richdocumentscode(_arm64)?\/proxy) /nextcloud/index.php$request_uri;
-
+            # Rewrite most PHP requests to Nextcloud's front controller
+            # (`/nextcloud/index.php`).
+            #
+            # (Mirrors the rewrite exceptions in Nextcloud's Apache .htaccess.)
+            #
+            # Exceptions (not rewritten; must remain directly reachable):
+            #   index.php, remote.php, public.php, cron.php, status.php
+            #   ocs/v1.php, ocs/v2.php, ocs-provider/*
+            #   core/ajax/update.php, updater/*
+            #   */richdocumentscode(_arm64)?/proxy
+            #
+            # Other exceptions (e.g. /.well-known) are handled by dedicated
+            # location blocks elsewhere in this config.
+            #
+            # Caution: small edits to this regex can break routing or introduce
+            # rewrite loops.
+            rewrite ^/nextcloud/(?!index|remote|public|cron|status|ocs\/v[12]|ocs-provider\/.+|core\/ajax\/update|updater\/.+|.+\/richdocumentscode(_arm64)?\/proxy) /nextcloud/index.php$request_uri;
+
+            # Split `/file.php/path/info` into:
+            # - $fastcgi_script_name: `/file.php`
+            # - $fastcgi_path_info:   `/path/info`
+            #
+            # This is required for entry-points such as `remote.php` and `public.php`,
+            # which route requests based on PATH_INFO.
             fastcgi_split_path_info ^(.+?\.php)(/.*)$;
-            set $path_info $fastcgi_path_info;
+            set $path_info $fastcgi_path_info;    # Save before try_files resets it
 
+            # Return 404 for nonexistent PHP scripts (avoids passing arbitrary
+            # paths to PHP-FPM, which is a known security risk).
             try_files $fastcgi_script_name =404;
 
             include fastcgi_params;
-            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
-            fastcgi_param PATH_INFO $path_info;
-            fastcgi_param HTTPS on;
-
-            fastcgi_param modHeadersAvailable true;         # Avoid sending the security headers twice
-            fastcgi_param front_controller_active true;     # Enable pretty urls
             fastcgi_pass php-handler;
 
+            fastcgi_param SCRIPT_FILENAME            $document_root$fastcgi_script_name;
+            fastcgi_param PATH_INFO                  $path_info;
+            fastcgi_param HTTPS                      on;       # Assumes TLS terminates here
+            fastcgi_param modHeadersAvailable        true;     # Avoid duplicate security headers
+            fastcgi_param front_controller_active    true;     # Enable pretty URLs
+
+            # Let nginx handle HTTP error responses from PHP-FPM (e.g. custom
+            # error pages). Disable for debugging if PHP errors are being hidden.
             fastcgi_intercept_errors on;
-            fastcgi_request_buffering on;                   # Required as PHP-FPM does not support chunked transfer encoding and requires a valid ContentLength header.
 
-            # PHP-FPM 504 response timeouts
-            # Uncomment and increase these if facing timeout errors during large file uploads
+            # Required for uploads: PHP-FPM does not support chunked
+            # transfer encoding and needs a Content-Length header.
+            fastcgi_request_buffering on;
+
+            # Optional PHP-FPM timeout tuning (e.g. for 504 response timeouts).
+            # Increase these only if uploads or long-running PHP requests are
+            # timing out in your environment.
             #fastcgi_read_timeout 60s;
             #fastcgi_send_timeout 60s;
             #fastcgi_connect_timeout 60s;
 
+            # Disable on-disk buffering of FastCGI responses (reduces disk I/O at
+            # the cost of holding responses in memory).
             fastcgi_max_temp_file_size 0;
         }