This idiom is fairly common in both social and professional situations. The bones of a business or a project can refer to the basic design or foundation upon which other decisions are made. The bones in a body make up the skeleton or the scaffolding on which everything else relies. This can also be used to talk about things like a club or some type of organisation, as in ‘the bones of the committee are made up of the chairman, secretary and the treasurer’; or even the details of something or something you’re working on, as in ‘I always write the bones of my essay first and go back to flesh it out later’.
We're moving house. The bones of it is that the rent has increased so much that we can't afford to live there anymore.
The bookshop owner tried to incorporate a coffee shop into his business, but it ended up costing too much to run. He decided that it would be best to stick to the basic bones of the business - selling books.