Make sure, that all headings in html structure taking place and have a right order

Steps to reproduce

This is accessibility issue.

Please make sure, that all appearance of heading in html taking place and have a right order.
Example (other app):

there are issues with the headings on several pages:

• Headings aren’t structured correctly to match the information structure
• In some places, headings skip levels
• Some headings aren’t marked up as such in the code
• Some content that aren’t headings are coded using heading-elements

Please check all modal windows and sidebars

Expected behavior

Sometimes heading is wrong. Please check / correct

Actual behaviour

Heading is there and have a correct order

Calendar app version

3.3.2

CalDAV-clients used

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Browser

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Client operating system

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Server operating system

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Web server

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Database engine version

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PHP engine version

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Nextcloud version

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Updated from an older installed version or fresh install

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List of activated apps

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Nextcloud configuration

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Web server error log

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Log file

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Browser log

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Additional info

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Start by reviewing the calendar app's modal windows and sidebars, checking heading markup and hierarchy across the affected pages. Done means headings reflect the information structure, levels do not skip, headings use heading elements, and non-heading content does not use them.