Simplify the following text for a Grade 9 native English-speaking person.
Original: He and Jon von Tetzchner were part of a research group at the Norwegian state phone company ( now known as Telenor ) where they developed browsing software called MultiTorg Opera .
Simplified: He and Jon Stephenson von Tetzchner were part of a research group at the Norwegian state telephone company ( now known as Telenor ) . They made browsing software called MultiTorg Opera .