It is not specified what format should be used to deliver the generic profile from an MNO to an SM-DP or SM-DP+ operator or in a SoftSIM/SoC eSIM application. There are various file formats that can be used to provide the profile e..g UXP, ASN.1 or even a simple Excel spreadsheet. The most commonly used format is UXP as specified by the SIM Alliance. This is called the SIM Profile Mark-up Language and is based on XML.
In addition a file of IMSI/Ki pairs must be generated in order to personalise the generic profile.