Web config File

web.config

<?xml version="1.0"?>    
<configuration>    
 <system.webServer>    
   <rewrite>    
     <rules>    
       <rule name="React Routes" stopProcessing="true">    
         <match url=".*" />    
         <conditions logicalGrouping="MatchAll">    
          <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />    
          <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />    
          <add input="{REQUEST_URI}" pattern="^/(api)" negate="true" />    
         </conditions>    
         <action type="Rewrite" url="/" />    
       </rule>    
     </rules>    
   </rewrite>    
 </system.webServer>    
</configuration>   

what do you punt here?
input="{REQUEST_FILENAME}"

and here
input="{REQUEST_URI}"