One more correction:
I changed my %KATALON\_STUDIO\_INSTALLED_FOLDER%\\katalon.ini file as follows:
-startup
plugins/org.eclipse.equinox.launcher_1.3.201.v20161025-1711.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_64_1.1.401.v20161122-1740
-data
config
-vmargs
-Xms256m
-Xmx4048m
-Dwebdriver.chrome.logfile=C:/temp/chromedriver.log
-Dwebdriver.firefox.logfile=C:/temp/firefoxdriver.log
And in the command line I did the following:
$ cd %KATALON_STUDIO_INSTALLED_FOLDER%
$ eclipsec.exe -clean
A window of Katalon Studio opened. Soon I closed it. Then, I started Katalon Studio as usual (by clicking desktop icons etc).
I did Record/Web Spy/Run TestCase using Chrome browser.
I got C:/temp/chromedriver.log file.
I did Record/Web Spy/Run TestCase using Firefox Browser.
I got C:/temp/firefoxdriver.log file as well.
“$ eclipsec.exe -clean” operation is necessary in order to clean the internal cache of Eclipse, and make my change in the katalon.ini file effective.