Why does "Automatically connect eligible plugs and slots of snap "okular"" take a relatively long time?

Solution 1:

It seems that

Automatically connect eligible plugs and slots of snap "..."

is just a way to indicate that supplementary material is being downloaded.

While the downloading of okular has a straightforward progress indicator, the time while "Automatically connect eligible plugs and slots of snap "..."" is in progress is denoted by just a rotating |.

However, if one keeps Ubuntu's system monitor open at the same time, it's quite evident that "Automatically connect eligible plugs and slots ..." means a download is in progress.

The process in the terminal and the downloading activity shown in the system conclude at the same time.

In the case of installing the okular snap on a clean (no other qt-dependent snap having been installed) Ubuntu 20.04, the supplementary material downloaded after the okular snap is kde-frameworks-5-qt-5-14-core18 5.68.0. Watching the network activity in the system monitor indicates that approximately 333 MiB were downloaded.

It's not a big deal but now I know that "Automatically connect eligible plugs and slots ..." means downloading stuff.