https://www.gsma.com/newsroom/wp-content/uploads//TS.25-v5.0.pdf

1 Scope

This permanent reference document (PRD), details the nature, structure and handling of the “Mobile (Network) Codes and Names” (TS.25 formerly SE13), how it can be submitted by Mobile Network Operators and how it is presented and made available to those wishing to receive the data. The primary purpose of collating and making available the network codes and names is to provide terminal vendors with network details to be displayed to users on mobile devices on the display or within the network selection menu.
运营商提交的TS.25数据，也就是PLMN Name是以SE13表的格式呈现的。

3 Registration Process

The GSMA hosts the “mobile network codes and names” data and when a member wishes to provide and register new or updated information, they should complete the Input Form Template in Section 3.1, using the guidance provided in this document (see section 4) and submit this information to the email address networkcodesandnames@gsma.com
The information received, will be processed within two weeks and updates will be provided to members that have subscribed to the mailing list to which updates are sent. To receive the latest updated TS.25 database please contact networkcodesandnames@gsma.com or view it under the tab, Roaming > Mobile Network Codes and Names or click here to view.
TS.25 database的提交方式和获取方式。最后的here是如下网站：https://infocentre2.gsma.com/roaming/SE13/Pages/default.aspx
该网站可以看到，除国内三大运营商外，还有小米、OPPO、华为、荣耀、中兴等公司是GSMA member。也就是说他们有权限下载该SE13表。

相关资料：
Official Document TS.44 - Operator Name Display on a Smartphones
https://www.gsma.com/newsroom/wp-content/uploads//TS.44-v1.0-2.pdf