strange safari behavior

Yesterday I posted a discussion where safari was trashed on my system. Whenever I invoked safari, I got a message saying "ios crash warning." safari was not functional. I was able to access the sites I needed to reach using chrome.

My wife input the error message I was getting into google and got the suggestion to start safari while holding down the shift key. I did that, and safari is functional now. I'm sending this message using safari.

Does anyone know how this worked? What happens when you invoke safari while holding the shift key?

I believe I had to hold the shift key only once. Subsequent invocations of safari were done normally.