Support has received questions in cases on the purpose of out-of-the-box system property: "glide.installation.production" and if it can be modified. There are similar questions posted on the ServiceNow Community as well.
The Development team has clarified that the use of this system property: "glide.installation.production" is for internal purposes such as zboots. This property should not be modified or used for other purposes as it may cause issues/data loss and the impact has not been tested/verified.
"glide.installation.production" should NOT to be used as a means to differentiate between Production and subproduction instances. If this is your requirement, please consider creating a custom system property and set the appropriate values for your Production and subproduction instances. Please also remember to preserve this custom system property in your subproduction instances so that it will not be overwritten by the clone process.