Rename optional feature build target to extras

ober

88d91a2fb0383671c59a5b8dfef1d80cec5b009c

diff --git a/.gitignore b/.gitignore
index 488f5eb..1b11ac8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,7 +11,7 @@
 *.ta6fb
 
 /jsh
-/jsh-options
+/jsh-extras
 /jsh-macos
 /jsh-macos.sha256
 /ffi-shim-symbols.list
diff --git a/Makefile b/Makefile
index 72fe91e..6833707 100644
--- a/Makefile
+++ b/Makefile
@@ -61,7 +61,7 @@ SH_SPEC := python3 $(CURDIR)/test/run_spec.py
 BASH := /bin/bash
 JSH ?= $(if $(filter Darwin,$(UNAME_S)),./jsh-macos,./jsh)
 
-.PHONY: ensure-jerboa-tools ensure-shell-extras options jerboa binary jsh jsh-macos macos run security test test-binary test-native \
+.PHONY: ensure-jerboa-tools ensure-shell-extras extras jerboa binary jsh jsh-macos macos run security test test-binary test-native \
         test-native-sanitize test-security-regressions adversarial-corpus audit \
         sbom reproducibility-report timing-evidence verify release-evidence \
         compat compat-smoke compat-tier0 compat-tier1 compat-tier2 compat-one compat-range compat-debug \
@@ -81,13 +81,17 @@ ensure-shell-extras:
 		echo "=== Fetching jerboa-shell-extras ==="; \
 		mkdir -p "$$(dirname "$(JERBOA_SHELL_EXTRAS_DIR)")"; \
 		git clone "$(JERBOA_SHELL_EXTRAS_URL)" "$(JERBOA_SHELL_EXTRAS_DIR)"; \
+	elif [ "$(JERBOA_SHELL_EXTRAS_DIR)" = "$(CURDIR)/_vendor/jerboa-shell-extras" ]; then \
+		echo "=== Updating jerboa-shell-extras ==="; \
+		git -C "$(JERBOA_SHELL_EXTRAS_DIR)" pull --ff-only; \
 	fi
+	@test -f "$(JERBOA_SHELL_EXTRAS_DIR)/Makefile"
 
-options: ensure-shell-extras
-	@$(MAKE) -C "$(JERBOA_SHELL_EXTRAS_DIR)" options \
+extras: ensure-shell-extras
+	@$(MAKE) -C "$(JERBOA_SHELL_EXTRAS_DIR)" extras \
 		JERBOA_SHELL_DIR="$(CURDIR)" \
 		JSH_EMBED="$(JERBOA_SHELL_EXTRAS_DIR)/embed" \
-		OPTIONS_OUTPUT="$(CURDIR)/jsh-options"
+		EXTRAS_OUTPUT="$(CURDIR)/jsh-extras"
 
 ffi-shim-symbols.list: ffi-shim.c tools/extract-ffi-symbols.sh Makefile
 	@echo "=== Regenerating FFI symbol whitelist from ffi-shim.c ==="
@@ -295,7 +299,7 @@ help:
 	@echo "Build:"
 	@echo "  make jsh-macos        Build the macOS binary"
 	@echo "  make jsh              Build and copy the native binary to ./jsh"
-	@echo "  make options          Select and build optional feature bundles"
+	@echo "  make extras           Select and build optional feature bundles"
 	@echo ""
 	@echo "Test:"
 	@echo "  make security         Release security metadata and secret scan"
diff --git a/README.md b/README.md
index 641f293..8cad42f 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,14 @@ The build uses `jerbuild` from Jerboa. The Makefile prefers `./jerbuild`, then
 `.jerboa/bin/jerbuild`, then `jerbuild` on `PATH`; if none are available it
 fetches the configured Jerboa release tool.
 
+The default targets build only the bare shell. To open the optional-feature
+menu, fetch the extras bundle and its selected dependencies, and produce
+`./jsh-extras`, run:
+
+```sh
+make extras
+```
+
 ## Test
 
 ```sh