diff --git a/.flake8 b/.flake8
index b67d9c2198..a1458f4e73 100644
--- a/.flake8
+++ b/.flake8
@@ -8,8 +8,7 @@ ignore =
 exclude =
   ./llvm
   ./gnu
-  ./upstream
-  ./fastcomp
+  ./prebuilt
   ./fastcomp-clang
   ./releases
   ./clang
diff --git a/.gitignore b/.gitignore
index 0d794d22d0..ab8006a1ff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,9 +15,7 @@ __pycache__
 # File that get download/extracted by emsdk itself
 /ccache
 /gnu
-/upstream
-/fastcomp
-/fastcomp-clang/
+/prebuilt
 /llvm
 /ninja
 /releases
diff --git a/README.md b/README.md
index 33c7c60c4b..6bb29d6fb1 100644
--- a/README.md
+++ b/README.md
@@ -136,11 +136,11 @@ using git, and compile the package on demand.
 When you run `emsdk list`, it will group the Tools and SDKs under these two
 categories.
 
-To obtain and build latest upstream wasm SDK from source, run
+To obtain and build latest wasm SDK from source, run
 
 ```
-emsdk install sdk-upstream-main-64bit
-emsdk activate sdk-upstream-main-64bit
+emsdk install sdk-main-64bit
+emsdk activate sdk-main-64bit
 ```
 
 You can use this target for example to bootstrap developing patches to LLVM,
@@ -156,7 +156,7 @@ https://emscripten.org/docs/contributing/developers_guide.html?highlight=develop
 ### When working on git branches compiled from source, how do I update to a newer compiler version?
 
 Unlike tags and precompiled versions, a few of the SDK packages are based on
-"moving" git branches and compiled from source (e.g. sdk-upstream-main,
+"moving" git branches and compiled from source (e.g. sdk-main,
 sdk-main, emscripten-main, binaryen-main). Because of that, the
 compiled versions will eventually go out of date as new commits are introduced
 to the development branches. To update an old compiled installation of one of
@@ -198,11 +198,11 @@ where you directly interact with the github repositories. This allows you to
 obtain new features and latest fixes immediately as they are pushed to the
 github repository, without having to wait for release to be tagged. You do not
 need a github account or a fork of Emscripten to do this. To switch to using the
-latest upstream git development branch `main`, run the following:
+latest git development branch `main`, run the following:
 
     emsdk install git-1.9.4 # Install git. Skip if the system already has it.
-    emsdk install sdk-upstream-main-64bit # Clone+pull the latest emscripten-core/emscripten/main.
-    emsdk activate sdk-upstream-main-64bit # Set the main SDK as the currently active one.
+    emsdk install sdk-main-64bit # Clone+pull the latest emscripten-core/emscripten/main.
+    emsdk activate sdk-main-64bit # Set the main SDK as the currently active one.
 
 ### How do I use my own Emscripten github fork with the SDK?
 
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 508d7b39b5..62817ca21c 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -32,11 +32,11 @@ RUN echo "## Install Emscripten" \
 RUN cd ${EMSDK} \
     && echo "## Generate standard configuration" \
     && ./emsdk activate ${EMSCRIPTEN_VERSION} \
-    && chmod 777 ${EMSDK}/upstream/emscripten \
-    && chmod -R 777 ${EMSDK}/upstream/emscripten/cache \
+    && chmod 777 ${EMSDK}/prebuilt/emscripten \
+    && chmod -R 777 ${EMSDK}/prebuilt/emscripten/cache \
     && echo "int main() { return 0; }" > hello.c \
-    && ${EMSDK}/upstream/emscripten/emcc -c hello.c \
-    && cat ${EMSDK}/upstream/emscripten/cache/sanity.txt \
+    && ${EMSDK}/prebuilt/emscripten/emcc -c hello.c \
+    && cat ${EMSDK}/prebuilt/emscripten/cache/sanity.txt \
     && echo "## Done"
 
 # Cleanup Emscripten installation and strip some symbols
@@ -45,11 +45,11 @@ RUN echo "## Aggressive optimization: Remove debug symbols" \
     # Remove debugging symbols from embedded node (extra 7MB)
     && strip -s `which node` \
     # Tests consume ~80MB disc space
-    && rm -fr ${EMSDK}/upstream/emscripten/tests \
+    && rm -fr ${EMSDK}/prebuilt/emscripten/tests \
     # Fastcomp is not supported
-    && rm -fr ${EMSDK}/upstream/fastcomp \
+    && rm -fr ${EMSDK}/prebuilt/fastcomp \
     # strip out symbols from clang (~extra 50MB disc space)
-    && find ${EMSDK}/upstream/bin -type f -exec strip -s {} + || true \
+    && find ${EMSDK}/prebuilt/bin -type f -exec strip -s {} + || true \
     && echo "## Done"
 
 # ------------------------------------------------------------------------------
@@ -65,7 +65,7 @@ COPY --from=stage_build /emsdk /emsdk
 # (sub-stages) or with custom / no entrypoint
 ENV EMSDK=/emsdk \
     EMSDK_NODE=/emsdk/node/14.18.2_64bit/bin/node \
-    PATH="/emsdk:/emsdk/upstream/emscripten:/emsdk/upstream/bin:/emsdk/node/14.18.2_64bit/bin:${PATH}"
+    PATH="/emsdk:/emsdk/prebuilt/emscripten:/emsdk/prebuilt/bin:/emsdk/node/14.18.2_64bit/bin:${PATH}"
 
 # ------------------------------------------------------------------------------
 # Create a 'standard` 1000:1000 user
diff --git a/emsdk.py b/emsdk.py
index 12bbb2c8fb..f3d37b188e 100644
--- a/emsdk.py
+++ b/emsdk.py
@@ -1919,9 +1919,9 @@ def install_sdk(self):
       return False
 
     if getattr(self, 'custom_install_script', None) == 'emscripten_npm_install':
-      # upstream tools have hardcoded paths that are not stored in emsdk_manifest.json registry
-      install_path = 'upstream'
-      emscripten_dir = os.path.join(EMSDK_PATH, install_path, 'emscripten')
+      # prebuilt sdk tools have hardcoded paths that are not stored in
+      # emsdk_manifest.json registry
+      emscripten_dir = os.path.join(EMSDK_PATH, 'prebuilt', 'emscripten')
       # Older versions of the sdk did not include the node_modules directory
       # and require `npm ci` to be run post-install
       if not os.path.exists(os.path.join(emscripten_dir, 'node_modules')):
@@ -2244,7 +2244,7 @@ def load_releases_info():
 
 
 def get_installed_sdk_version():
-  version_file = sdk_path(os.path.join('upstream', '.emsdk_version'))
+  version_file = sdk_path(os.path.join('prebuilt', '.emsdk_version'))
   if not os.path.exists(version_file):
     return None
   with open(version_file) as f:
diff --git a/emsdk_manifest.json b/emsdk_manifest.json
index 927cdd9bf7..d0510fd89d 100644
--- a/emsdk_manifest.json
+++ b/emsdk_manifest.json
@@ -38,7 +38,7 @@
     "macos_url": "https://storage.googleapis.com/webassembly/emscripten-releases-builds/mac/%releases-tag%/wasm-binaries.tbz2",
     "windows_url": "https://storage.googleapis.com/webassembly/emscripten-releases-builds/win/%releases-tag%/wasm-binaries.zip",
     "zipfile_prefix": "%releases-tag%-",
-    "install_path": "upstream",
+    "install_path": "prebuilt",
     "activated_path": "%installation_dir%/emscripten",
     "activated_cfg": "LLVM_ROOT='%installation_dir%/bin';BINARYEN_ROOT='%installation_dir%';EMSCRIPTEN_ROOT='%installation_dir%/emscripten'",
     "emscripten_releases_hash": "%releases-tag%"
@@ -51,7 +51,7 @@
     "macos_url": "https://storage.googleapis.com/webassembly/emscripten-releases-builds/mac/%releases-tag%/wasm-binaries-arm64.tbz2",
     "linux_url": "https://storage.googleapis.com/webassembly/emscripten-releases-builds/linux/%releases-tag%/wasm-binaries-arm64.tbz2",
     "zipfile_prefix": "%releases-tag%-",
-    "install_path": "upstream",
+    "install_path": "prebuilt",
     "activated_path": "%installation_dir%/emscripten",
     "activated_cfg": "LLVM_ROOT='%installation_dir%/bin';BINARYEN_ROOT='%installation_dir%';EMSCRIPTEN_ROOT='%installation_dir%/emscripten'",
     "emscripten_releases_hash": "%releases-tag%"
diff --git a/test/test_activation.ps1 b/test/test_activation.ps1
index 6d38ffcbd8..851244a8b0 100644
--- a/test/test_activation.ps1
+++ b/test/test_activation.ps1
@@ -58,9 +58,9 @@ try {
         throw "$repo_root\\node is not added to path."
     }
 
-    $EMSDK_UPSTREAM_Path = $path_split | Where-Object { $_ -like "$repo_root\upstream\emscripten*" }
+    $EMSDK_UPSTREAM_Path = $path_split | Where-Object { $_ -like "$repo_root\prebuilt\emscripten*" }
     if (!$EMSDK_UPSTREAM_Path) {
-        throw "$repo_root\\upstream\emscripten is not added to path."
+        throw "$repo_root\\prebuilt\emscripten is not added to path."
     }
 
 
diff --git a/test/test_path_preservation.ps1 b/test/test_path_preservation.ps1
index 1547949967..d25bdddcb5 100644
--- a/test/test_path_preservation.ps1
+++ b/test/test_path_preservation.ps1
@@ -42,7 +42,7 @@ try {
     $EMSDK_NODE_Path = $path_arr | Where-Object { $_ -like "$repo_root\node*" }
     $EMSDK_PYTHON_Path = $path_arr | Where-Object { $_ -like "$repo_root\python*" }
     $EMSDK_JAVA_Path = $path_arr | Where-Object { $_ -like "$repo_root\java*" }
-    $EMSDK_UPSTREAM_Path = $path_arr | Where-Object { $_ -like "$repo_root\upstream\emscripten*" }
+    $EMSDK_UPSTREAM_Path = $path_arr | Where-Object { $_ -like "$repo_root\prebuilt\emscripten*" }
 
     $number_of_items = $path_arr.count
     [System.Collections.ArrayList]$rest_of_path = @()
@@ -52,7 +52,7 @@ try {
             ($item -like "$repo_root\node*") -or
             ($item -like "$repo_root\python*") -or
             ($item -like "$repo_root\java*") -or
-            ($item -like "$repo_root\upstream\emscripten*")
+            ($item -like "$repo_root\prebuilt\emscripten*")
         ) {
             echo "$item is on the PATH"
         }