All OTRS configurations are saved in 3 config files named "config.pm", "ZZZAuto.pm" and "ZZZAAuto.pm". OTRS in order to retrieve any specific configuration entry, searches these files in a special order. If a specific entry is found in a config file, other config files are not searched. By this, "config.pm" has higher priority than "ZZZAuto.pm" and "ZZZAuto.pm" itself has a higher priority than "ZZZAAuto.pm". I dub "ZZZAuto.pm" tiny config file and dub "ZZZAAuto.pm" the main config file afterward.
It’s possible to change all entries of main config file via SysConfig through UI. Consider that there are some special config entries that does not exists in main config file. One example is database connection string. Such settings can not be edited by SysConfig. Main config never changes but tiny config file is changed everytime you change an entry via SysConfig.
If you’re going to change an entry that currently resides in "config.pm", the only way is changing "config.pm" directly even that entry contains in either main or tiny config files. In the other hand, SysConfig saves your changes in tiny config file but it does not take effect because a same entry exists in "config.pm".
Using SysConfig you can download all OTRS configurations except those that are not present in main config file (like database connection string). This config file indeed is our lovely tiny config file that it is downloaded for users. You can change this downloaded file, add or edit your desired entries and then upload them back to OTRS again. By uploading a new configuration file, this new uploaded file is replaced with OTRS tiny config file.
