Each time the install script runs it creates a log file with a date and time stamp name, for example
INSTALL_DIR/log/2019-02-05-18-08-35.log
where INSTALL_DIR is the directory where you un-PAXed the Zowe PAX file. It contains useful information to help diagnose problems that may occur during an install. This file is also copied across into the runtime folder into which Zowe is installed, for example
ZOWE_RUNTIME/install_log/2019-02-05-18-08-35.log
where ZOWE_RUNTIME is the directory where you installed the Zowe runtime files.