Steps to reproduce the issue

• I have installed a plugin with version 2021.07.12 with no compatibilty entry for Joomla 4 in update xml file.
• For testing purposes I added a new version 2021.07.13 in the update xml file and added Joomla 4 compatibilty <targetplatform name="joomla" version=".*" />.
• Go into Pre-Update-Checker > "Check For Updates". It tells me that an update to 2021.07.13 is required for this plugin. Correct.
• Go into Extensions > Update. Click "Check For Updates". It tells me that an update to 2021.07.13 is available for this plugin. Correct.
• I changed the update xml file and removed version 2021.07.13. I changed it to already installed 2021.07.12.
• I checked that the changed file is delivered correctly from the update server.
• I checked that Joomla uses this file via "Update Sites".
• Go into Pre-Update-Checker. Click "Check for updates". It still shows me version 2021.07.13. WRONG.
• Go into Extensions > Update. Click "Check For Updates". It tells me that an update to 2021.07.13 is available for this plugin. WRONG.
• I clicked several times "Check For Updates". No change.
• Deleted browser caches, Joomla cache tells me that there is "no cached content", logged out from Joomla, logged in again.
• Go into Extensions > Update. Click "Check For Updates". It tells me that an update to 2021.07.13 is available for this plugin. WRONG.

Expected result

• In Joomla 3 we have an additional button in Extensions > Update "Clear Cache". It does what it says.
• In Joomla 4 I found no way to clear the extension cache immediately and I had to wait 10 to 15 minutes before the wrong version was removed. Many clicks, reopening and things.

Question

• Where is the update data cached in Joomla 4 and where/how can I delete it immediately like in Joomla 3 without delay?