About FLASH writing to "DE C0 AD DE FE 01 1E F1"

SDK: 15.3.0
Example: ble_app_multirole_lesc
Device: EYSHJNZWZ (nRF52832)

I called "pm_init" to do "PeerManager".
Then, a part of FLASH has been written to "DE C0 AD DE FE 01 1E F1".
Please tell me the cause of this.
Also, please tell me the meaning of this written value.