[jcn363]

This is not `Remove extra bottom space when footer disabled` but... when you enable `Show footer` you can adjust it with:

Spoiler:

Reduce reading footer and quit caption:
  - Enabled: no
  - Description: |
      Based on GeoffR's `Custom reading footer style`
  - FindReplaceString:
      Find:    "ReadingFooter {\n  qproperty-footerMargin: 105;\n}\n\
                ReadingFooter[qApp_deviceIsDragon=true] {\n  qproperty-footerMargin: 170;\n}\n\
                ReadingFooter[qApp_deviceIsDaylight=true] {\n  qproperty-footerMargin: 221;\n}\n\
                #caption[qApp_deviceIsTrilogy=true] {\n  font-size: 19px;\n}\n\
                #caption[qApp_deviceIsPhoenix=true] {\n  font-size: 23px;\n}\n\
                #caption[qApp_deviceIsDragon=true] {\n  font-size: 29px;\n}\n\
                #caption[qApp_deviceIsAlyssum=true] {\n  font-size: 32px;\n}\n\
                #caption[qApp_deviceIsNova=true] {\n  font-size: 32px;\n}\n\
                #caption[qApp_deviceIsDaylight=true] {\n  font-size: 37px;\n}\n\
                #caption[qApp_localeName=\"ja_JP\"] {\n  font-family: Sans-SerifJP, sans-serif;\n  font-style: normal;\n}"
# When editing the replacement values below,
# BE CAREFUL NOT TO CHANGE THE LENGTH OF THE REPLACEMENT STRING!
      Replace: "ReadingFooter {qproperty-footerMargin: 00; min-height: 15px; max-height: 15px;}\n\
                #caption{qproperty-visible:false;}\n                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         "
      MustMatchLength: yes

Good luck.