diff --git a/runtime/doc/pack.txt b/runtime/doc/pack.txt
index 29482354af..285ad08bfc 100644
--- a/runtime/doc/pack.txt
+++ b/runtime/doc/pack.txt
@@ -211,7 +211,9 @@ WORK IN PROGRESS built-in plugin manager! Early testing of existing features
 is appreciated, but expect breaking changes without notice.
 
 Manages plugins only in a dedicated *vim.pack-directory* (see |packages|):
-`$XDG_DATA_HOME/nvim/site/pack/core/opt`. Plugin's subdirectory name matches
+`$XDG_DATA_HOME/nvim/site/pack/core/opt`. `$XDG_DATA_HOME/nvim/site` needs to
+be part of 'packpath'. It usually is, but might not be in cases like |--clean|
+or setting |$XDG_DATA_HOME| during startup. Plugin's subdirectory name matches
 plugin's name in specification. It is assumed that all plugins in the
 directory are managed exclusively by `vim.pack`.
 
diff --git a/runtime/lua/vim/pack.lua b/runtime/lua/vim/pack.lua
index ea3007731d..279d8a1d66 100644
--- a/runtime/lua/vim/pack.lua
+++ b/runtime/lua/vim/pack.lua
@@ -4,7 +4,9 @@
 ---is appreciated, but expect breaking changes without notice.
 ---
 ---Manages plugins only in a dedicated [vim.pack-directory]() (see |packages|):
----`$XDG_DATA_HOME/nvim/site/pack/core/opt`.
+---`$XDG_DATA_HOME/nvim/site/pack/core/opt`. `$XDG_DATA_HOME/nvim/site` needs to
+---be part of 'packpath'. It usually is, but might not be in cases like |--clean| or
+---setting |$XDG_DATA_HOME| during startup.
 ---Plugin's subdirectory name matches plugin's name in specification.
 ---It is assumed that all plugins in the directory are managed exclusively by `vim.pack`.
 ---