Hi, I'm about to install a water softener. I know it needs to be connected between the outside water and the house water lines but someone decided to connect those two lines in an additional location and wondering why.
The red line is the main water supply.
The blue line is the outside water for irrigation and sillcocks.
The yellow line goes to the rest of the house and water heater.

For some reason someone connected the yellow and blue further down the line with the green PEX line shown in the picture. Any idea why this would be needed?

I plan to remove the green line and allow the blue and yellow to run clear past that spot and then install the softener on the red line between the blue and yellow down below.

My only concern was if that green line served any purpose?

I can't tell from the picture where those lines go so what purpose they serve is unknown but you can trace them all from source to location and figure what they are for, and if they are needed and what should be done about them. How old is the house?

"My only concern was if that green line served any purpose?"

I see no reason for the green line. Perhaps someone was installing a bypass line in case one of the lines developed an issue, but if they were doing that they are missing a couple shutoff valves and did not finish the bypass. If that is the case, then the green line, unfinished, serves no purpose and can be removed.

Mark