Calendar subpage using table tags with missing class attributes

Problem/Motivation

I'm not sure if this is a new feature to perform changes or just a little oversight, but the version 8.x-1.0-beta1 is using table tags on calendar subpage instead of custom divs forcing developers to perform CSS updates for whole calendar section.
Is it possible to switch back to standard div tags or to add missing class attributes for new tags?

At this moment I manually updated 8.x-1.0-alpha4 for D10 compatibility and there are no table tags or CSS issues.

Steps to reproduce

Compare versions 8.x-1.0-beta1 with 8.x-1.0-alpha4 on calendar subpage. There are differences in calendar structure.

Proposed resolution

Switch back table, tr, td tags to divs or add missing class attributes for those tags, for example 'calendar-row' where's now empty <tr> tag only or another <tr> containing 'date-box' class attribute instead of previous 'multi-day' one.

Remaining tasks

User interface changes

API changes

Data model changes