[Nexus 4 Original Android Development] banjker:
I agree, this would be very useful. In the mean time, you can download the update manually, extract system.new.dat from the zip, load it into your favorite editor and search for 'changelog.txt' (I used Notepad++). Here it is for the 10-4 build

10-04-2015
====================

* packages/apps/Settings/
0f3fd20 Changelog: prettify [pcarenza]
* vendor/xenonhd/
c5faa46 Change changelog separator [pcarenza]

====================
10-03-2015
====================

* device/lge/g3-common/
0435835 audio: kill off remaining offload props and config [dadi11]
* device/samsung/qcom-common/
7522278 Automatic translation import [Michael Bestas]
* frameworks/webview/
cadb80d Update Webview to current [pcarenza]
282062e Revert "webview: arm: 45.0.2454.87 to 45.0.2454.95" [Daniel Sikorski (dadi11)]
* hardware/qcom/fm/
5585419 Automatic translation import [Michael Bestas]
* kernel/samsung/jf/
3e0912c msm: mdp: Restore PCC config when MDP goes on [JosÃ© Adolfo GaldÃ¡mez]
* packages/apps/AudioFX/
b65b58e Automatic translation import [Michael Bestas]
* packages/apps/Eleven/
38f0dcd Automatic translation import [Michael Bestas]
* packages/apps/LockClock/
cf85872 Automatic translation import [Michael Bestas]
* packages/apps/SlimLauncher/
8cf9336 Fix force close with some icon packs [Griffin Millender]

====================
10-02-2015
====================

* vendor/xenonhd/
a68b550 Get rid of duplicate products dirs [pcarenza]

====================
10-01-2015
====================

* kernel/lge/g3/
cfd63b7 msm: mdss: kcal: Only apply updates on index 0 [dadi11]
591dd17 msm: mdss: kcal: Use PCC for negative display mode [dadi11]
59d64ea arm/dts: lge: Enable bam_dmux fast shutdown [dadi11]
de23600 soc: qcom: bam_dmux: Add fast-shutdown flag [dadi11]

====================
09-30-2015
====================

* build/
4026f56 Fix amend alias [pcarenza]
* device/samsung/klte-common/
178c704 usb: don't start adb if not enabled in debugging [Ethan Chen]
795e4be usb: add "charging" option [Ethan Chen]
* vendor/samsung/
3be3a0d Merge pull request #656 from christer12/cm-12.1 [Ethan Chen]
0a3b3c3 Merge pull request #657 from gekkehenkie11/cm-12.1 [Ethan Chen]
* vendor/xenonhd/
1563c63 Make changelog more informative [pcarenza]

====================
09-29-2015
====================

====================
09-28-2015
====================

* device/samsung/qcom-common/
2ff8617 recovery/root: Add msm8916 postrecoveryboot support [Dan Pasanen]
* kernel/oneplus/msm8974-caf/
2e41cd8 asoc: wcd9xxx: Sweet MBHC lovins [pcarenza]
67e9848 ASoC: wcd9xxx-mbhc: Add PLUG_TYPE_HIGH_HPH to fast-detection path [pcarenza]
6f07b01 ASoC: wcd9xxx-mbhc: Introduce fast detection for audio jack [pcarenza]
362b80b ASoC: wcd9xxx-mbhc: Ignore button interrupts during plug detection [pcarenza]
690c6d4 ASoC: wcd9xxx-mbhc: Reduce detection time for PLUG_TYPE_HEADSET [pcarenza]
1003eb8 power: qpnp-charger: Restore charge current to max after thermal throttle [pcarenza]
17035b1 power: qpnp-charger: Update thermal thresholds [pcarenza]
* vendor/samsung/
e4894c6 trlte-common: add libmysound.so [gekkehenkie11]
9d716b6 hlte-common: update bluetooth and add aDSP [Christer]

You could also try running the generating script manually (I didn't try it) https://github.com/TeamHorizon/vendor_xenonhd/blob/lp-mr1/tools/changelog