diff --git a/home/programs/git.nix b/home/programs/git.nix
index 88f90ba8..7acd24aa 100644
--- a/home/programs/git.nix
+++ b/home/programs/git.nix
@@ -10,13 +10,13 @@
 
     # all my ssh private key are generated by `ssh-keygen -t ed25519 -C "ryan@nickname"`
     # the config's format:
-    #   Host — the nickname you’ll use for the host.
-    #   HostName — the IP address or domain of the remote server.
-    #   User — the username associated with the remote account.
+    #   Host —  given the pattern used to match against the host name given on the command line.
+    #   HostName — specify nickname or abbreviation for host
     #   IdentityFile — the location of your SSH key authentication file for the account.
+    # format in details:
+    #   https://www.ssh.com/academy/ssh/config
     extraConfig = ''
-      Host Homelab
-        Hostname 192.168.*
+      Host 192.168.*
         # allow to securely use local SSH agent to authenticate on the remote machine.
         # It has the same effect as adding cli option `ssh -A user@host`
         ForwardAgent yes
@@ -26,8 +26,7 @@
         # required to prevent sending default identity files first.
         IdentitiesOnly yes
 
-      Host GitHub
-          Hostname github.com
+      Host github.com
           # github is controlled by gluttony~
           IdentityFile ~/.ssh/gluttony
           # Specifies that ssh should only use the identity file explicitly configured above
@@ -38,6 +37,7 @@
     # use ssh-agent so we only need to input passphrase once
     # run `ssh-add /path/to/key` for every identity file
     # check imported keys by `ssh-add -l`
+    # TODO `ssh-add` can only add keys temporary, use gnome-keyring to unlock all keys after login.
   };
 
   programs.git = {
diff --git a/home/programs/xdg.nix b/home/programs/xdg.nix
index f386accd..251d38d0 100644
--- a/home/programs/xdg.nix
+++ b/home/programs/xdg.nix
@@ -11,7 +11,6 @@
     "application/xhtml+xml" = browser;
     "text/html" = browser;
     "x-scheme-handler/about" = browser;
-    # "x-scheme-handler/chrome" = ["chromium-browser.desktop"];
     "x-scheme-handler/ftp" = browser;
     "x-scheme-handler/http" = browser;
     "x-scheme-handler/https" = browser;
@@ -21,9 +20,8 @@
     "video/*" = ["mpv.dekstop"];
     "image/*" = ["imv.desktop"];
     "application/json" = browser;
-    "application/pdf" = ["org.pwmt.zathura.desktop.desktop"];  # TODO: pdf viewer
+    "application/pdf" = browser;  # TODO: pdf viewer
     "x-scheme-handler/discord" = ["discord.desktop"];
-    "x-scheme-handler/spotify" = ["spotify.desktop"];
     "x-scheme-handler/tg" = ["telegramdesktop.desktop"];
   };
 in {