Write-Information output currently does not use an INFO: prefix when printing its output to the console.

This contrast with the Write-Verbose, Write-Warning, and Write-Debug cmdlets, all of which use an analogous prefix when printing to the console, so as to make it easier to distinguish data (success) output from output to other streams.

Curiously, however, when you transcribe a session (Start-Transcript), the INFO: prefix is present.
(Discrepancies between console-output and transcription behavior are summarized in #4645
and are being at least partially addressed in PR #6917).

Note that changing console output so show INFO: too wouldn't technically be a breaking change - for-display output is not part of the contract with the user - but it would be a noticeable one.

Current behavior

PS> Write-Information hi -InformationAction Continue
hi

Behavior that would be consistent with other Write-* cmdlets (except Write-Output)

PS> Write-Information hi -InformationAction Continue
INFO: hi

Environment data

Written as of:

PowerShell Core v6.1.0-preview.2