minecraft-packets/minecraft-packets/data/pc/1.19.3/from-server/system_chat/1.json

An easy way to query PrismarineJS/minecraft-packets

{
  "content": "{\"italic\":true,\"color\":\"gray\",\"translate\":\"chat.type.admin\",\"with\":[{\"text\":\"Server\"},{\"translate\":\"commands.op.success\",\"with\":[\"nmptestbot\"]}]}",
  "isActionBar": false
}