The Global Certification Forum ( GCF ) is an industry body primarily representing Original Equipment Manufacturers ( OEMs ). It provides a certification process for consumer eUICCs which is described on their web site.
In addition they are developing a standard for SoC eSIMs.
The GSMA ( GSM Association ) is a trade body that primarily represents Mobile Network Operators ( MNOs ).
It is the primary driving force behind the eUICC form of eSIM and has an early working group looking at SoC eSIM.
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.