You should be using this already, but it is a master because I happened to have it enabled at the time of making the mod.
Permissions and credits
Credits and distribution permission
Other user's assetsAll the assets in this file belong to the author, or are from free-to-use modder's resources
Upload permissionYou are not allowed to upload this file to other sites under any circumstances
Modification permissionYou are allowed to modify my files and release bug fixes or improve on the features so long as you credit me as the original creator
Conversion permissionYou can convert this file to work with other games as long as you credit me as the creator of the file
Asset use permissionYou are allowed to use the assets in this file without permission as long as you credit me
Asset use permission in mods/files that are being soldYou are not allowed to use assets from this file in any mods/files that are being sold, for money, on Steam Workshop or other platforms
Asset use permission in mods/files that earn donation pointsYou are allowed to earn Donation Points for your mods if they use my assets
Author notes
If you want to make a patch that integrates this mod with another, please make this mod a master. If you want to take this mod for a larger project (eg overhauling many interiors across Skyrim) then feel free to do so, but please credit this mod.
File credits
This author has not credited anyone else in this file
I decided to make this since I don't know of any mods affecting the building already, and a large number of players will see it in-game - as it's required for the Dark Brotherhood. It's also a way for me to improve with the Creation Kit, to the ends of being able to make full-sized mods.
HOW This uses all vanilla assets, so very small download size. If you want the fairest comparison of vanilla to this mod, the last set of images (the ones not using an ENB) are entirely vanilla except for the mod.
WHAT I checked through the Elder Scrolls wiki to ensure I did nothing that's lore-breaking, and I didn't add anything crazy. The most valuable/powerful items added are an Ebony Dagger (replaces default iron dagger, on top of the book near the black sacrament), and a Daedra Heart. I also added a short book back from Oblivion (The Five Tenets) - but the main focus is on lighting and static objects. It's so homely you want to live there!
TKV6 images courtesy of Cuddle Poro, who provided great advice and support throughout the making of the mod.