Most of Lepton GUI applications and TUI utilities use the same logging mechanism. All important info gets into log files. The log files of the tools are usually located in the cache directory of the suite which is usually ~/.cache/lepton-eda/logs. We store several last logs for each utility and rotate them, that is, remove old ones after adding new.
The log files are named as follows: ‘toolname-date-number.log’. For example, ‘lepton-archive-20201113-4.log’.
If you suspect some utility did something wrong, or it failed and crashed, consult the logs in the first place. The same matters for GUI utilites as well. Open the mostly recent file and look in there. For user convenience, the log files have the date in their names and, besides, the files of the same date are subsequently numbered. Among several files with same date, the file having the greater number as the suffix of its basename is the last stored log.
In lepton-schematic, you can watch the log messages without the need to
open any files, of course if you do not seek to learn the reason why
the program crashed just now. See Log window.