While we await for the 6th synthesis report in September this year, the 169 page synthesis report from 2014 is available.
Around the time the synthesis report was released, the Working Group I report was released The Physical Science Basis. The WG I report is 1,535 pages and the PDF weights 375Mb. I have an earlier version ("final draft") that weights 159Mb with 2,216 pages.
The idea is to provide an interactive summary of the content, potentially tying together to a Wikipedia dump and incorporation research in user-tailored text summarization, that is, incorporating explanations of concepts the user is not familiar. Might also be worth tying some parts to the IE4OpenData project.
There might be useful tools to incorporate in this effort from communities working with collections of research papers related to the COVID-19 pandemic. For example, the LitCovid effort, with a 2Gb annotated research paper collection available for download.
While a tool to learn about the IPCC WGI efforts will be very useful, it will have to be made a standalone tool. The report can be cited but it cannot be made web-accessible.