The IRS has issued Notice 2020-23 (linked here), which extends to July 15, 2020, the deadline for taking certain “time-sensitive actions” that were required to be taken on or after April 1, 2020, and before July 15, 2020.
These “time-sensitive actions” include filing Form 8038 or 8038-G (thus extending the deadline to July 15 for 8038s for bonds issued in the first quarter of 2020) and making any rebate or yield reduction payments that would have been due during that window and filing Form 8038-T.
The full list of time-sensitive actions is included in Section III.A of the Notice, and includes the time-sensitive actions relating to tax-exempt bonds described in Section 16 of Revenue Procedure 2018-58 (linked here).