Specific SharePoint applications and services as well as tools, like SharePoint Designer tend to store their own settings in the property bag of web sites. Especially root webs of site collection have a lot of properties.
You can display the web properties from PowerShell like:
$web = Get-SPWeb http://YourSharePointSite
$web.AllProperties
The problem, that the above script displays really all of the properties, and the list is not alphabetically sorted, so it might be challenging to find a specific property.
The properties and their values are stored as key-value pairs in a Hashtable object, you can filter these entries as described in this thread. For example, the script below displays the search related entries, the ones whose names begin with SRCH.
$web.AllProperties.GetEnumerator() | ? Key -like ‘SRCH*’
Although it is not so common, you can filter the entries based on its values as well. For example, this script display all properties having a value of True:
$web.AllProperties.GetEnumerator() | ? Value -eq ‘True’
If all you want is to display the properties sorted alphabetically by their names, it is easy to achieve either:
$web.AllProperties.GetEnumerator() | Sort-Object -Property Key
Of course, all of these possibilities apply not only to the property bags of web objects (SPWeb.AllProperties), but to other property bags as well, like the properties of the folders (SPFolder.Properties) and files (SPFile.Properties) or lists (SPLists.Properties) and list items (SPListItem.Properties).