The property to replace. The syntax depends on the group's format.

JSON - dotted navigation, with quoting for keys that contain dots:

• Logging.LogLevel.Default - three nested objects
• Serilog.'MinimumLevel.Default' - a literal key containing dots
• Services[0].Url - zero-based array index

XML - shorthands for the two .NET configuration collections:

• appSettings.ApiUrl - the value attribute of the matching entry
• appSettings.BankApi:Key - colons and dots are literal here, never navigation
• connectionStrings.Default - the connection string
• connectionStrings.Default.@providerName - the provider name instead

Matching is exact and case-sensitive. Only entries directly inside the top-level appSettings or connectionStrings element are considered; entries inside <location> and external files referenced by file= are not.

XML - anything else is reached by walking elements from the document root, ending in .@attribute or .#text:

• configuration.'system.webServer'.security.requestFiltering.requestLimits.@maxAllowedContentLength - a nested attribute; note that an element name containing a dot must be quoted
• configuration.branding.title.#text - the element's own text
• configuration.'system.webServer'.handlers.add[1].@name - the second matching sibling, zero-based
• configuration.location.'system.web'.authorization.deny.@users - content inside <location>, which the shorthands do not reach

Element names match exactly as written, namespace prefix included. If a step matches more than one sibling and carries no index, the build fails rather than guessing which one you meant - add [0], [1] and so on to choose. Missing elements and attributes are reported as missing paths and are never created.

.#text replaces everything between the tags, indentation included, so an element written across several lines collapses onto one. This is the only case in which a substitution changes whitespace. It also requires the element to hold text and nothing else - one containing child elements, comments or CDATA is reported as ambiguous rather than having its markup overwritten.