Help me understand these system track entities

I’m using Dorico 4 SE. When I look at the system track, I often see the little pink boxes with something like “4/4 (q,1+1+1+1)” in them scattered through the song. I don’t know what they are, what they do, what I did that put them there, or what they’re for, but I do know that deleting them wreaks absolute havoc on the score. Bar lines disappear, note values change, lyrics get massively messed up, and so forth. So, I leave them alone! But I would like to understand what they are and what they do and get a better handle on managing them. I’ve read the sections in the manual about the system track, but I haven’t found any descriptions of these things. I don’t expect people here to go to great lengths, but some explanation and pointers to helpful materials would be much appreciated. Thanks! I’ve attached a screenshot to show what I’m talking about. I know that for most kinds of troubleshooting it’s better to post the project, but this isn’t troubleshooting; this is just ignorance-shooting. Thanks much in advance!

These aren’t in the system track, they’re signposts. They indicate (probably in this case) an explicit barline at that location. They can also indicate hidden meter changes.

Try selecting the barlines just before the second one and following, and pressing Delete.

Or, depending whether SE has this option, you can hide the signposts in the View menu.

The System Track is the thing above the system, which you can use to select and delete complete bars for all the staves.

As said, a time signature signpost either represents a hidden object, or something like a pick-up bar, or a custom note grouping.