diff --git a/README.md b/README.md
index 73ac1752..c1b7db15 100644
--- a/README.md
+++ b/README.md
@@ -165,12 +165,12 @@ add_executable(foo main.cpp)
 target_link_libraries(foo PRIVATE etl::etl)
 ```
 
+Alternatively you can use [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html).
 
-Alternatively you can use [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html),
-replacing `<targetVersion>` with the version to install based on a git tag:
+By Git, replacing `<targetVersion>` with the version to install based on a git tag:
 
-```sh
-Include(FetchContent)
+```cmake
+include(FetchContent)
 
 FetchContent_Declare(
   etl
@@ -184,6 +184,25 @@ add_executable(foo main.cpp)
 target_link_libraries(foo PRIVATE etl::etl)
 ```
 
+Or by URL, fetching a release tarball directly, again replacing `<targetVersion>` with the desired version:
+
+```cmake
+include(FetchContent)
+
+FetchContent_Declare(
+  etl
+  URL https://github.com/ETLCPP/etl/archive/refs/tags/<targetVersion>.tar.gz
+)
+
+FetchContent_MakeAvailable(etl)
+
+add_executable(foo main.cpp)
+target_link_libraries(foo PRIVATE etl::etl)
+```
+
+A tarball fetched this way has no `.git` directory of its own. ETL detects this and falls back to
+reading its version from `version.txt` instead of `git describe`, so no extra configuration is needed.
+
 ## Profile definition
 
 When using ETL in a project, there is typically an `etl_profile.h` defined to
diff --git a/cmake/GetGitRevisionDescription.cmake b/cmake/GetGitRevisionDescription.cmake
index d0966da1..d45b2101 100644
--- a/cmake/GetGitRevisionDescription.cmake
+++ b/cmake/GetGitRevisionDescription.cmake
@@ -82,6 +82,19 @@ function(etl_get_git_head_revision _refspecvar _hashvar)
             set(GIT_DIR "")
         endif()
     endif()
+    if(NOT "${GIT_DIR}" STREQUAL "")
+        # Reject a .git dir that belongs to a parent project (e.g. when fetched
+        # as a URL tarball with no .git of its own and _etl_git_find_closest_git_dir
+        # walked up into the consuming project's repository). Gated by the same
+        # flag as above, since CMAKE_CURRENT_SOURCE_DIR is always at or below
+        # CMAKE_SOURCE_DIR, so this check is strictly tighter than the one above
+        # and must honor the same opt-out.
+        file(RELATIVE_PATH _relative_etl_to_git "${CMAKE_CURRENT_SOURCE_DIR}"
+             "${GIT_DIR}")
+        if("${_relative_etl_to_git}" MATCHES "^[.][.]" AND NOT ALLOW_LOOKING_ABOVE_CMAKE_SOURCE_DIR)
+            set(GIT_DIR "")
+        endif()
+    endif()
     if("${GIT_DIR}" STREQUAL "")
         set(${_refspecvar}
             "GITDIR-NOTFOUND"