The Prior Information Group Properties pane is on the PEST Properties dialog box under Prior Information.
The variables specified on the Prior Information Group Properties pane are described in the PEST User Manual, Part I, Section 4.10. More extensive descriptions of these variables are in the PEST user manual. The variables specified on this pane appear in the Observation Groups section of the PEST control file.
OBGNME is the name of the observation group. Observation group names can be up to 12 characters in length. However, if an observation group is used for regularization, its name must be start with the prefix "regul_" which means that the rest of the group name can only be 6 characters in length. The prefix will be automatically added if the check box in the Regularization Group column is checked. Prior information groups typically are regularization groups but regular observation groups typically are not regularization groups.
GTARG is an optional group-specific target measurement objective function. To include it, check the check box in the Use Group Target column and specify the value in the Group Target column.
COVFLE If a covariance matrix is used for observation weights assignment for a particular observation group, COVFLE is the name of the file holding the covariance matrix for that group. The roles of observation and prior information covariance matrices are discussed in section 3.7 of the PEST User Manual and in Doherty (2015). The formatting of observation covariance matrix files is discussed in section 4.19 of the PEST User Manual.
Usually prior information is used for regularization. Clicking the button at the top of the pane will check all the check boxes in the Regularization Group column.
