diff --git a/Makefile b/Makefile
index 7aaf7921..4bdef4bd 100644
--- a/Makefile
+++ b/Makefile
@@ -43,6 +43,17 @@ SORTIX_RELEASE_DIR?=release
 SORTIX_REPOSITORY_DIR?=repository
 SORTIX_ISO_COMPRESSION?=xz
 
+SORTIX_INCLUDE_SOURCE_GIT_REPO?=$(shell test -d .git && echo "file://`pwd`")
+SORTIX_INCLUDE_SOURCE_GIT_REPO:=$(SORTIX_INCLUDE_SOURCE_GIT_REPO)
+SORTIX_INCLUDE_SOURCE_GIT_ORIGIN?=
+SORTIX_INCLUDE_SOURCE_GIT_CLONE_OPTIONS?=--single-branch
+SORTIX_INCLUDE_SOURCE_GIT_BRANCHES?=master
+ifneq ($(and $(shell which git 2>/dev/null),$(SORTIX_INCLUDE_SOURCE_GIT_REPO)),)
+  SORTIX_INCLUDE_SOURCE?=git
+else
+  SORTIX_INCLUDE_SOURCE?=yes
+endif
+
 include build-aux/dirs.mak
 
 BUILD_NAME:=sortix-$(VERSION)-$(MACHINE)
@@ -189,6 +200,19 @@ sysroot-system: sysroot-fsh sysroot-base-headers
 
 .PHONY: sysroot-source
 sysroot-source: sysroot-fsh
+ifeq ($(SORTIX_INCLUDE_SOURCE),git)
+	rm -rf "$(SYSROOT)/src"
+	git clone --no-hardlinks $(SORTIX_INCLUDE_SOURCE_GIT_CLONE_OPTIONS) -- $(SORTIX_INCLUDE_SOURCE_GIT_REPO) "$(SYSROOT)/src"
+	-cd "$(SYSROOT)/src" && for BRANCH in $(SORTIX_INCLUDE_SOURCE_GIT_BRANCHES); do \
+	  git fetch origin $$BRANCH && \
+	  git branch -f $$BRANCH FETCH_HEAD ; \
+	done
+ifneq ($(SORTIX_INCLUDE_SOURCE_GIT_ORIGIN),)
+	cd "$(SYSROOT)/src" && git remote set-url origin $(SORTIX_INCLUDE_SOURCE_GIT_ORIGIN)
+else
+	-cd "$(SYSROOT)/src" && git remote rm origin
+endif
+else ifneq ($(SORTIX_INCLUDE_SOURCE),no)
 	cp .gitignore -t "$(SYSROOT)/src"
 	cp COPYING-GPL -t "$(SYSROOT)/src"
 	cp COPYING-LGPL -t "$(SYSROOT)/src"
@@ -196,6 +220,7 @@ sysroot-source: sysroot-fsh
 	cp README -t "$(SYSROOT)/src"
 	cp -RT build-aux "$(SYSROOT)/src/build-aux"
 	(for D in $(MODULES); do (cp -R $$D -t "$(SYSROOT)/src" && $(MAKE) -C "$(SYSROOT)/src/$$D" clean) || exit $$?; done)
+endif
 	(cd "$(SYSROOT)" && find .) | sed 's/\.//' | \
 	grep -E '^/src(/.*)?$$' | \
 	LC_ALL=C sort > "$(SYSROOT)/tix/manifest/src"
diff --git a/share/man/man7/development.7 b/share/man/man7/development.7
index 766a0a25..6197061b 100644
--- a/share/man/man7/development.7
+++ b/share/man/man7/development.7
@@ -8,8 +8,10 @@
 .Pa /src
 .Sh DESCRIPTION
 Releases come with the system source code in
-.Pa /src .
-It can be modified, compiled and installed on the current system.
+.Pa /src
+as a
+.Xr git 1
+repository.  It can be modified, compiled and installed on the current system.
 The source code is built with a
 .Xr make 1
 build system.  The source code can be located in any location, if so, simply
@@ -138,6 +140,19 @@ Specifies compiler optimization options that gets added to
 .Ev CFLAGS
 and
 .Ev CXXFLAGS .
+.It Ev SORTIX_INCLUDE_SOURCE
+Specifies whether the source code is included in the sysroot.  This must be one
+of
+.Sy no, yes
+or
+.Sy git
+and defaults to
+.Sy git
+if
+.Xr git 1
+is installed and
+.Sy yes
+otherwise.
 .It Ev SORTIX_ISO_COMPRESSION
 Specifies the compression algorithm used in iso files.  This must be one of
 .Sy none , gzip
@@ -251,6 +266,30 @@ as not all ports can be built natively yet.
 .Pp
 The ports system is described in detail in
 .Xr porting-guide 7 .
+.Ss Patches
+The source code is managed as a
+.Xr git 1
+repository and you can make your own changes and commit them.  A good approach
+is to set up your own local development branch and work there:
+.Bd -literal
+    git checkout -b local
+    git add utils/hello.c
+    git commit -m 'Add hello(1).'
+.Ed
+.Pp
+You can then easily prepare your a set of patches for upstream submission:
+.Bd -literal
+    git format-patch master..local
+.Ed
+.Pp
+This will create a series of .patch files containing your changes.  Review them
+and rewrite git history as needed until they are of submittable quality. You can
+then submit them for review at the official website.
+.Pp
+To transfer files out of the operating system, you can either mount the local
+root filesystem from another operating system with networking, or you transmit
+the patches over the serial connection as described in
+.Xr serial-transfer 7 .
 .Ss Releases
 CD-ROM release of the operating system can be built with the
 .Sy iso
@@ -272,7 +311,9 @@ target and prepare a
 directory with a directory structure and miscellaneous files suitable for a
 formal online release.
 .Sh SEE ALSO
+.Xr git 1 ,
 .Xr make 1 ,
 .Xr cross-development 7 ,
 .Xr porting-guide 7 ,
+.Xr serial-transfer 7 ,
 .Xr update-initrd 8
diff --git a/share/man/man7/user-guide.7 b/share/man/man7/user-guide.7
index 4215e8d7..549510cd 100644
--- a/share/man/man7/user-guide.7
+++ b/share/man/man7/user-guide.7
@@ -83,7 +83,9 @@ file lists all currently installed ports.
 .Ss Source Code
 Releases come full with the system source code in
 .Pa /src
-along with the tools to build it and develop it.  The build
+as a
+.Xr git 1
+repository along with the tools to build it and develop it.  The build
 process is covered in
 .Xr development 7 .
 .Ss Mounting