What does 'git commit' mean when it says 'create mode ...' on stdout?

Question

EDIT:

See Danny Lin's git-store-meta as a proposed solution to the versioning-metadata problem described below. I have yet to test it as of 2015-05-13.

ORIGINAL QUESTION:

Do the create|delete mode ... lines in the git commit output (example below) represent some sort of metadata control? (And/or, what do these lines represent in general?) These appear to be unix-like file-permission codes/representations, although I'm not sure -exactly- the mapping, but the bigger question is: what if anything does git do with these codes/settings/values? Does git attempt to leverage these saved codes in any way to prove helpful to solve metadata problems my per superuser.com question "How to reuse/extend etckeeper's metadata engine for git control of non-/etc filesystems, or extend git natively with said capability?"? I'm aware that git doesn't control all filesystem metadata.

[Git does apparently, already control the "executeable attribute/perm" of a file (apparently portable for most OSes) and some other things like filesystem links. I'm seeking a more Unix/Linux/BSD/DarwinMacOSX-specific control mechanism for more/all metadata, namely all permissions and user/group ownership. ACLs and other metadata control optional. Trying to see if the stuff git is currently storing might prove useful to solve this problem.]

root@node1 Dec 15 09:40:45 ~/.../sandbox-1# git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   README
#   new file:   dummy-file-will-be-removed
#   deleted:    ownerfile
#
root@node1 Dec 15 09:40:45 ~/.../sandbox-1# git commit -m "testing git"
[master c5b0201] testing git
 2 files changed, 1 insertions(+), 2 deletions(-)
 create mode 100644 dummy-file-will-be-removed
 delete mode 100644 ownerfile
root@node1 Dec 15 09:41:55 ~/.../sandbox-1# 
[...]
root@node1 Dec 15 11:33:11 ~# git --version
git version 1.7.4.1
root@node1 Dec 15 11:33:14 ~# 

Answer 1

For more information about Git's mode, see this answer.

Git's ability to store file metadata is limited to a simple subset of information to allow Git to track some basic file system changes allowing Git to track relevant changes for source code management; such as whether a file has been modified and whether a file is a regular file or an executable file.

Git does not try to implement any notion of a file system, leaving file system routines to an actual file system implementation. This makes good sense to allow Git to work equally whether on a FAT32, NTFS, EXT3, XFS, NFS, etc. file system running on Linux, MacOS, Windows, etc.