Features & non-features:
- it would generally work like the reader mode (no other modes) trying to place navigation links in a predictable place
- user can easily select text size and color schemes
- night mode (Android does not have one)
- because of it's content focus it could offer great offline capabilities like full-text search through archive and version comparison
- probably ignore most or all CSS
- probably no JavaScript support
- ad blocker for the rest
Can such a thing use it's own rendering engine on iOS? As I said I don't care about JS.
[0] https://en.wikipedia.org/wiki/Links_(web_browser)