Life In 19x19

I also have some questions about KaTrain. KaTrain and KataGo were installed using Debian Linux,
and the pip3 installation method.

I tried to upload a screen shot as a PNG or JPEG file, but both attempts failed.

1. What do the red triangles and dots do? There is a dotted triangle at the
bottom left pointing left and one at the bottom right pointing right.

2. What is the meaning of the green disk at the bottom right? Sometimes it
contains numbers which slowly decrease in value. Are they counting moves or
seconds or what?

3. I somehow got the impression that KaTrain can review a collection of games
by the same person and build a curated set of SGF problem files designed to
rectify their most important weaknesses. I cannot now find any source for this
information, so I probably made it up out of thin air. Does such a thing
exist? If so, how does it work? The nearest I have found is the comments
which KaTrain adds to individual game records when it saves them after
analysis. (This is similar to the functionality that I wrote using Linux
scripts to annotate SGF files saved by KataGo via Lizzie. My
scripts are less verbose and only address my perceived needs.)

I'm still using an older version of katrain, version 1.10.1, but since there aren't any responses yet I'll answer you questions based on my experience.

thirdfogie wrote:1. What do the red triangles and dots do? There is a dotted triangle at the
bottom left pointing left and one at the bottom right pointing right.

Those are probably supposed to look like arrows, they jump to the next 'mistake' (for a lack of better word). The 'mistakes' are moves marked with orange or worse color, when you select "Show Dots". This is configurable under a menu item called "Teaching/Analyses Settings". I seldom use this bottom but at first I used it a lot, it is a good way to jump around in the game to find larger mistakes.

thirdfogie wrote:2. What is the meaning of the green disk at the bottom right? Sometimes it
contains numbers which slowly decrease in value. Are they counting moves or
seconds or what?

This is, I believe, the "Engine status" indicator. When I click on it the following is printed somewhere in the program.

This simply indicates the Engine status, going from green (idle) to orange (processing queries). It turns red when the engine has crashed or fails to start.

Sometimes it is half-and-half green and yellow or yellow and orange. In both cases I have always detect a failure.

When there are numbers displayed on the disk it is the number of pending requests.

thirdfogie wrote:3. I somehow got the impression that KaTrain can review a collection of games
by the same person and build a curated set of SGF problem files designed to
rectify their most important weaknesses.

This is not in the version I'm using.