diff --git a/src/feather/config.default.toml b/src/feather/config.default.toml
index 1b12c4a..5487dd4 100644
--- a/src/feather/config.default.toml
+++ b/src/feather/config.default.toml
@@ -6,6 +6,7 @@
 [server]
 # (Required) Server API to use. Either "googlereader" for the Google Reader API (FreshRSS, Miniflux, etc.) or "ttrss" for the TinyTiny-RSS API.
 # The Google Reader API do not support nested categories.
+# Can be set through the environment variable SERVER_API.
 api = "googlereader"
 # (Required) URL of your server's Google Reader API endpoint
 # Can be set through the environment variable SERVER_URL.
@@ -138,6 +139,7 @@ hide_empty_categories = true
 # Can be set through the environment variable HTML_MAX_FILENAME_LENGTH.
 max_filename_length = 250
 # Table mapping characters to what they will be replaced with in filenames. Useful to remove/replace characters that are not allowed in filename by your filesystem. The default should be fine for most Unix filesystems.
+# Can not be set through environment variables, sorry!
 filename_replacement = { "/" = "⧸", "\u0000" = "" }
 
 [datetime]