update docs/maintain as per audit 1

Signed-off-by: Leah Rowe <info@minifree.org>

site/docs/maintain/index.md

@@ -120,12 +120,6 @@ The files under `bin/` are provided in regular Canoeboot releases.
 **These** are the ROM images that you should flash. Do *not* flash the ROM
 images contained under `elf/`!
 
-cbutils/
----------------
-
-The build system compiles `cbfstool` and `ifdtool`, from coreboot, and then
-places the executables here for use on coreboot ROM images.
-
 elf/
 ---------------
 
@@ -149,6 +143,10 @@ cbmk in your own custom coreboot ROM (that you didn't build with cbmk).
 This is only used by the build system, but these images are *not* provided in
 releases (only the images under `bin/` are provided).
 
+As of Canoeboot 20240612, the `elf/` directory must be used by default for all
+builds, in an effort to make exclusive use of *out-of-source builds*. As such,
+the `cbutils` directory is no longer used.
+
 release/
 ---------------
 
@@ -461,6 +459,7 @@ as:
 * `release="n"` (example entry)
 * `xtree="default"` (example entry)
 * `tree_depend="default"` (example entry)
+* `grubtree="nvme"` (example entry)
 
 The `tree` value refers to `config/coreboot/TREE`; in other words, a given
 target could specify a name other than its own as the tree; it would then
@@ -524,6 +523,9 @@ a given board; two trees may use the same crossgcc as each other.
 The `tree_depend` option means that a given tree needs another tree, defined
 by this variable, to also be present.
 
+The `grubtree` option specifies which GRUB tree to use. If unset, it defers to
+the `default` GRUB tree.
+
 ### config/coreboot/BOARDNAME/config/
 
 Files in this directory are *coreboot* configuration files. 
@@ -630,18 +632,18 @@ of their own; for example, `config/grub/` exists.
 Multiple files exist here, and they are *concatenated* in a temporary file by
 cbmk, which is then scanned to find information about projects.
 
-config/grub/
+GRUB config
 ---------------
 
-### config/grub/background
+### config/data/grub/background
 
 Splash screen images applied duing startup when using the GRUB payload.
 
-### config/grub/background/background1024x768.png
+### config/data/grub/background/background1024x768.png
 
 Used on ThinkPad X60 and T60.
 
-### config/grub/background/background1280x800.png
+### config/data/grub/background/background1280x800.png
 
 Used on all other machines, besides X60 and T60 thinkpads.
 
@@ -651,23 +653,15 @@ example, `config/coreboot/x60/target.cfg` specifies this:
 
 	grub_background="background1024x768.png"
 
-### config/grub/background/COPYING
+### config/data/grub/background/COPYING
 
 Licensing info for GRUB bootsplash images.
 
-### config/grub/config/
+### config/grub/TREE/config/
 
 GRUB configuration files.
 
-### config/grub/config/AUTHORS
+### config/grub/TREE/config/grub.cfg
-
-Author info for GRUB configuration files.
-
-### config/grub/config/COPYING
-
-Licensing info for GRUB configuration files.
-
-### config/grub/config/grub.cfg
 
 This is a configuration file. It is used to program GRUB's shell.
 
@@ -681,7 +675,7 @@ A `grubtest.cfg` can be inserted into CBFS, but it will not override the
 default `grub.cfg` (either in CBFS or on memdisk); however, the one in memdisk
 will provide a menuentry for switching to this, if available.
 
-### config/grub/config/grub\_memdisk.cfg
+### config/data/grub/memdisk.cfg
 
 This GRUB configuration checks whether `grub.cfg` exists in CBFS and switches
 to that first (not provided by default) or, if one is not available in CBFS,
@@ -691,12 +685,12 @@ The GRUB memdisk is a file system within `grub.elf`, itself stored within the
 coreboot file system named *CBFS*, which is part of the coreboot ROM image on
 every coreboot target.
 
-### config/grub/keymap/
+### config/data/grub/keymap/
 
 Keymap files used by GRUB. They can alter the character set corresponding to
 inputted scancodes.
 
-### config/grub/keymap/\*.gkb
+### config/data/grub/keymap/\*.gkb
 
 The keymap files themselves. These are inserted into the GRUB memdisk, and
 the `grub.cfg` file can specify which one is to be used.
@@ -705,7 +699,7 @@ These files are binary-encoded, defining which characters correspond to which
 scancodes. It is handled by `grub-core/commands/keylayouts.c` in the GRUB source
 code.
 
-### config/grub/modules.list
+### config/data/grub/modules/TREE
 
 This defines which modules are inserted into `grub.elf`. These modules can be
 anything from file systems, small applications/utilities, launchers (e.g.
@@ -871,6 +865,56 @@ Another interesting config option is `CONFIG_POSITION_INDEPENDENT` for ARM
 boards, which has been so far enabled in the ones `cbmk` supports, just to be
 safe.
 
+config/submodule
+----------------
+
+In here you can find submodule configurations for projects. It works for both
+single- and multi-tree projects. Use the existing examples as reference.
+
+Files, in each directory:
+
+* `module.list` lists paths (files and directories) for given modules, which
+  can be files(via URL) or Git repositories, or both.
+* NAME/module.cfg
+
+NAME is the file/directory name for the module, with everything up to the
+final forward slash removed. E.g. foo/bar/thing.zip would be thing.zip as
+NAME.
+
+In `module.cfg` there can be either, file:
+
+```
+subfile="url"
+subfile_bkup="url"
+subhash="sha512sum for file"
+```
+
+or, git repository:
+
+```
+subrepo="url"
+subrepo_bkup="url"
+subhash="sha1 git commit id"
+```
+
+You must only use `subfile` or `subrepo`, not both, and there must be a backup
+URL. The build system intentionally *avoids* using Git's actual submodules
+feature, instead opting to download such repositories manually, because the
+official submodules feature doesn't have very good redundancy.
+
+Additionally, a `patches` directory can be included alongside `module.cfg`,
+which can be used to patch the submodule (only supported for Git repositories
+because files are not extracted, only placed at their configured destination).
+
+The destination path in `module.list` is relative to the location of the main
+Git repository under which it is placed.
+
+config/data/PROJECT
+-------------------
+
+Random configuration data provided on a per-project basis. Complements
+the `config/PROJECT` directory.
+
 U-Boot build system
 -------------------