I'm a long-term user and developer of TeX. I'm now retired from the Open University in the UK, where I was the LaTeX officer. My talk on Portable TeX Documents is based on my experience of problems in packaging TeX, informed by my knowledge of Python, Elm and Debian.
Both software and documents have dependencies. This talk focuses on managing document dependencies, to reduce both network and computation latency, and to ensure reproducible build (or typesetting) behaviour. Web development has a strong focus on reducing user experienced latency, as does serverless cloud computing.
At present human activity and large downloads are required to achieve these goals for TeX documents. To improve matters the speaker has introduced the concept of Portable TeX Documents (PTD). The PTD concept is intended to bring to source documents and the TeX community benefits similar to the benefits Portable Document Format (PDF) brought to Word users and Adobe.
The concepts and tools underlying PTD, particularly mounting git as a read-only file system, and the use of git backing stores (alternate object databases) are likely to be useful elsewhere. This is particularly true when most of the variability of a system lies in a small folder of text files (which is the case for TeX's typesetting inputs).