The /scoreboard players operation command tab completes fake players for the first but not the second name argument.
Additionally the syntax help calls it "selector" instead of "name":
- Add an objective
- Set for the fake player #fakePlayer a score
- Enter the following command and try to tab complete the fake player for both name arguments
Based on 1.11.2 decompiled using MCP 9.35 rc1
The method net.minecraft.command.server.CommandScoreboard.getTabCompletions(MinecraftServer, ICommandSender, String, BlockPos) uses only online players for the second name argument.