diff --git a/doc/doxygen/src/kconfig/kconfig.md b/doc/doxygen/src/kconfig/kconfig.md
index 873347d4a8..2c163f4af9 100644
--- a/doc/doxygen/src/kconfig/kconfig.md
+++ b/doc/doxygen/src/kconfig/kconfig.md
@@ -352,7 +352,9 @@ Features may be provided by any hierarchy symbol. Usually symbols are selected
 from more specific to less specific. This means that a `CPU_MODEL_<model>`
 symbol usually would select the correspondent `CPU_FAM_<family>` symbol,
 which would in turn select the `CPU_CORE_<core>`. This may change in some cases
-where `CPU_COMMON_` symbols are defined to avoid repetition.
+where `CPU_COMMON_` symbols are defined to avoid repetition. For convenience and
+if it makes sense within a CPU vendor family, it's also allowed to use
+intermediate grouping levels, like `CPU_LINE_<xxx>` used for STM32.
 
 In addition to the symbols of the hierarchy described above, a default value
 to the `CPU` symbol should be assigned, which will match the value of the `CPU`