location optional_modifier location_match {
    . . .
}

• If no modifiers are present, the location is interpreted as a prefix match.
• =: If an equal sign is used, this block will be considered a match if the request URI exactly matches the location given.
• ~: If a tilde modifier is present, this location will be interpreted as a case-sensitive regular expression match.
• ~*: If a tilde and asterisk modifier is used, the location block will be interpreted as a case-insensitive regular expression match.
• ^~: If a carat and tilde modifier is present, and if this block is selected as the best non-regular expression match, regular expression matching will not take place.

https://www.digitalocean.com/community/tutorials/understanding-nginx-server-and-location-block-selection-algorithms