In the command line those lines were seen:

$ krusader
17:57:02.657-debug default unknown@0 # System icon theme: "ubuntu-mono-dark"
17:57:08.929-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/16/"
17:57:08.929-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/22/"
17:57:08.930-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/24/"
17:57:08.930-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/32/"
17:57:08.930-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/48/"
17:57:08.931-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/64/"
17:57:08.931-warning default unknown@0 # Invalid Context= "stock" line for icon theme:  "/usr/share/icons/ubuntu-mono-dark/stock/128/"

17:57:14.144-warning default unknown@0 # QWidget::insertAction: Attempt to insert null action
17:57:14.169-warning default unknown@0 # QWidget::insertAction: Attempt to insert null action
17:57:14.464-warning default unknown@0 # Trying to convert empty KLocalizedString to QString.

17:57:17.020-warning default unknown@0 # Unable to find icon "view-choose" of size QSize(32, 32) in any configured theme
17:57:17.139-warning default unknown@0 # Unable to find icon "color-picker" of size QSize(32, 32) in any configured theme
17:57:17.196-warning default unknown@0 # Unable to find icon "tools-wizard" of size QSize(32, 32) in any configured theme
17:57:25.003-warning default unknown@0 # Unable to find icon "dialog-messages" of size QSize(32, 32) in any configured theme
17:57:25.139-warning default unknown@0 # Unable to find icon "utilities-file-archiver" of size QSize(32, 32) in any configured theme
17:57:28.863-warning default unknown@0 # Unable to find icon "debug-run" of size QSize(32, 32) in any configured theme
17:57:28.958-warning default unknown@0 # Unable to find icon "user-properties" of size QSize(32, 32) in any configured theme

17:57:40.295-warning kf5.kservice.services unknown@0 # KMimeTypeTrader: mimeType "all/allfiles" not found

17:57:46.996-warning default unknown@0 # Unable to find icon "chronometer" of size QSize(16, 16) in any configured theme
17:57:47.007-warning default unknown@0 # Unable to find icon "bookmarks" of size QSize(16, 16) in any configured theme
17:57:47.234-warning default unknown@0 # Unable to find icon "arrow-up" of size QSize(16, 16) in any configured theme
17:57:47.353-warning default unknown@0 # Unable to find icon "edit-select-none" of size QSize(22, 22) in any configured theme
17:57:47.378-warning default unknown@0 # Unable to find icon "edit-select" of size QSize(22, 22) in any configured theme
17:57:47.635-warning default unknown@0 # Unable to find icon "user-identity" of size QSize(22, 22) in any configured theme
17:57:50.572-warning default unknown@0 # Unable to find icon "inode-chardevice" of size QSize(22, 22) in any configured theme
17:57:52.139-warning default unknown@0 # Unable to find icon "user-identity" of size QSize(22, 22) in any configured theme
17:57:53.692-warning default unknown@0 # Unable to find icon "edit-select" of size QSize(22, 22) in any configured theme
17:57:53.721-warning default unknown@0 # Unable to find icon "edit-select-none" of size QSize(22, 22) in any configured theme
17:59:00.441-warning default unknown@0 # Unable to find icon "configure" of size QSize(16, 16) in any configured theme
17:59:00.978-warning default unknown@0 # Unable to find icon "configure" of size QSize(16, 16) in any configured theme
18:00:44.403-warning default unknown@0 # Unable to find icon "application-x-zerosize" of size QSize(22, 22) in any configured theme