Test-Utf8BomHeader.ps1

function Test-Utf8BomHeader {
    [CmdletBinding(DefaultParameterSetName = "File")]
    [OutputType([bool])]
    param(
        [Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, ParameterSetName = "File")]
        [System.IO.FileInfo]$File,

        [Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, ParameterSetName = "Path")]
        [Alias("LiteralPath", "PSPath")]
        [string]$Path
    )

    process {
        if ($PSBoundParameters.ContainsKey("File")) {
            $header = [FileHeader]::Read($File, $removeOffset)
            Write-Output ($header -eq $bomHex)
        }
        else {
            $header = [FileHeader]::Read($Path, $removeOffset)
            Write-Output ($header -eq $bomHex)
        }
    }
}