I'm assuming they mean "the dashboard", the page that shows at `
https://github.com/` if you're logged in. That page has the latest changes from people you follow, recent blog posts from GitHub, etc. Pretty useless IMHO.
The answer to OP's question is that there is no plugin for this, there is a URL for this. If they type in "github.com" in their browser that is what they will get, but if they bookmark the page they want to go to (or select it enough times among the address bars' suggestions) it will automatically become the first suggestion for "git<enter>". A surprising Ask HN indeed.
Or use this GreaseMonkey script:
if(window.location.href == 'https://github.com/') {
window.location.href = 'https://github.com/aliqot?tab=repositories';
}