Edge can be analytical (think: quant funds), informational (think: l/s equity funds), or behavioral (think: short sellers).
Edge itself is something in the process that gives you a more complete picture than others. For example, if you run a private survey of sales managers at various firms, you can develop an informational edge by getting color from legit sources on general conditions within the economy or industry. If the market price reflects the average of all views, edge is your advantage over the average.
Note: there’s a difference between edge and risk. For example, every talking head is discussing the Russia-Ukraine situation. You might think there won’t be a war, and load up on SPX futures. That is not an edge, that is risk.
Edge would be you having information such as talking to someone in Putin’s inner circle who tells you Putin doesn’t want to invade but needs a win diplomatically). Edge needs to come directly from a source and can’t be third-party or it’s just risk. “My professor friend who studies Russia says war not likely to happen” is risk not edge.